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June 10, 2013

Problems on Ages with Shortcuts

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Age, a period of human life measured by years from birth, some people have 15 years, some may have 32 years and some good people like me always have 22 years (of course I am 22 from last 3 years, now don't ask me how). Generally you may get 3 replies when you tried to know anybody's age.
  1. They may tell you their true age.
  2. They may tell you some false and standard age (like me).
  3. Or you may return rubbing your cheek with sad face if the answerer was an unknown girl.
But, the people in our competitive exams are lil different. They wont answer any question in direct manner. Instead of it saying a number, they just will say you some fraction or ratio, or just link their age to their relatives' or friend's age and ask you to guess their age. Ofcourse it sounds irritating. Usually we give a dirty look at the person and let him / her go in their way. But in exams, we don't have any other option except finding their real age. So here are some shortcut techniques to made the process of finding ages easier.We shall discuss the tricks with some examples so that you easily can understand them.

1. The average age of Khan, Kapoor, Kumar, Bachhan and Roshan is 28 years. The average age of Bachhan and Roshan is 25 years. What is the average age of Khan, Kapoor and Kumar ?

Solution :

Here 5 persons' average ( Khan, Kapoor, Kumar, Bachhan and Roshan) age is  = 28 Years.

That means their total age = 5 X 28 = 140 Years.

similarly, average age of two persons (Bachhan and Roshan)  is 25 years.
aptitude questions on ages with solutions
So their total age = 25 X 2 = 50 Years.

here 140 years is the total age of 5 persons             ( Khan, Kapoor, Kumar, Bachhan and Roshan)
50 years is the total age of 2 persons (Bachhan and Roshan)

So obviously, the total age of Khan, Kapoor and Kumar = Total age of  ( Khan, Kapoor, Kumar, Bachhan and Roshan) - Total age of (Bachhan and Roshan)

= 140-50 = 90 years.

But here we need average age of these 3 persons.

=> 90/3  = 30 Years

Shortcut Method :

((5 X 28) - (2 X 25)) / 3 =  (140-50)/ 3 = 90/3 = 30 Years


2. The ratio between the ages of Kareena and Sonam is 5:8 respectively and difference between their ages after 5 years will be 12 years. What is the present age of Kareena ?

Solution :
Usually for these type of questions people start with present age as X and adding 5 to get the ages after 5 years and later solve those equations. But its very time consuming.

A simple logic here is if the age difference between you and your friend is 8 years, after 5 or 10 years also the difference will be same. Hope you are getting what I am trying to say ;)

now see, the ratio between their ages is 5 : 8 

That means their actual ages will be some 5X and 8X

Then the difference between their ages is 5X-8X
in the question it is given that the difference is 12 years =>  5X-8X = 12  => 3X=12  => X = 4

So obviously Kareena's age = 5(4) = 20


3. Abhi is 30 years younger than his mother Jaya. Five years ago, Abhi was 1/4 as old as his mother was. How old is Abhi today ?

Solution :

5 years ago the ratio between their ages was Abhi : Jay a= 1X : 4X

we know that Hari is 30 years younger than Jaya. That means the difference between their ages is 30.

=>   3X = 30  => X = 10.

But this is the age of 5 years ago. So, the present age will be =10+5 = 15 Years

4. At present the ratio of the ages of Anand and Milind is 4 : 7 respectively. 6 years hence it will be 7 : 10 respectively. What is the present age of Milind ?

Solution :

Present ratio of their ages is 4 : 7 (So their present ages will be 4X, 7X)

After six years it will be of 7 : 10

=> (4x+6) : (7x+6) = 7 : 10

=> 40x + 60 = 49X + 42 (Cross Multiplication)

=> 9x = 18

=> x = 2                          

So Milind's present age will be 7X2 = 14 Years

Shortcut :

There is a shortcut formula for finding X



here, New ratio difference is 3, Added number is 6 (years)
Cross multiplication difference is 49-40 = 9

=>       X = (3 x 6) / 9  = 2



So Milind's present age will be 7X2 = 14 Years

5. Ten years ago the ratio between the ages of Mohan and Suman was 3:5 respectively. 11 years hence it will be 11:16 respectively. What is the present age of Mohan?

Solution :

 10 years ago 3x : 5x  -------------> Old Ratio

11 years hence  11x : 16x       ------------->  New Ratio

here the difference between ages is 21 years (10 years ago + 11 years hence)

apply above formula here

New ratio difference is (16-11) = 5

Added or substracted number (difference between ages) is = 21

Old and new ratios cross multiplication difference is = 55 - 48 = 7

==> X = (5 x 21) / 7 = 15

present age of mohan is = his age of 10 years ago + 10
                               
                                            = 3x15 + 10 = 55 years

6. Amar is as much younger than Raja as he is older than Kiran. If the ages of Amar and Raja are 30 years and 36 years respectively, what is the age of Kiran now ?

Solution :
Simple logic....
Amar is as much younger than Raja as he is older than Kiran. Try to understand this sentence. According to this sentence you can understand that
  • Amar is younger than Raja that means there is some X years difference between Amar and Raja.
  • Amar is older than Kiranwith same age difference (X years) between Amar and Kiran.

But we know that the ages of Amar and Raja are 30 and 36 years.

So the difference between their ages is = 6 years

So the difference between Amar and Kiran should be = 6 years.

We know the age of Amar as 30 years and Kiran is younger than Amar for 6 years. So he should be of 24 years.

With a single glance you can calculate answer for these type of problems.


7. The average age of a class of 20 students is 20 years. When the age of the teacher is also included, the average will be increased by 2 years. What is the age of the teacher ?

Solution :
Simple logic,
we know that 20 students' average = 20 years
20 people total age = 20 x 20 = 400 years

Including Teacher's

21 people average = 22 years

21 people total age = 21 x 22 = 462

we know the age of 20 students = 400 Yeras

we know the age of 21 people (20 students+ Teacher) = 462

so the age of Teacher will be 462-400 = 62 Years

8. The average age of a wife and husband, who were married 10 years ago, was 20 years then. Including a child the present average age of the family is 23 years. What is the present age of the child?

Solution :

10 year's ago average age = 20 years
10 year's ago total age = 20 x 2 = 40 years.

to calculate their present total age, you should add 20 (10 for wife and 10 for husband) to the age of 10 years ago

=> 40+20 = 60 years (this is the present age of husband and wife)    ----------- (1)

according to the given data, present average age of the family of 3 members is = 23 years

so Total age of 3 members = 23 x 3 = 69 years. ------------------(2)

but we know the present age of Husband and Wife = 60 years

so from equations (1) and (2), we can get the present age of the child is = 9 years


9. Five years ago the average age of a family of five members was 27 years then. Including a child the present average age is still same today. What is the age of the child now ?

Solution :

5 years back average = 27 years

present average should be 5 +27 = 32 Years

So total age of the 5 members at present = 5 x 32 = 160 years  -----------------(1)

but its given that including the child, the present average is 27 years.

=>   the total age of 6 members at present = 6 x 27 = 162 years -----------------(2) 

so from (1) and (2), you can easily get that the present age of the child is 2 years



10. The ratio between the ages of Karan and Arjun is 9:5 and sum of their ages at present is 56 years. How old will karan be after 4 years ?


Solution :

according to given data their ages should be 9x, 5x

their present age = 9x+5x = 56  ==> 14x = 56

so x = 4

so present age of Karan is 9 x 4 = 36 years

after 4 years, 36+4 = 40 years :)


Note : To explain the calculation process in clear, we have mentioned these many steps for every problem. But in exams you should do almost all of these calculations mentally and try to avoid writing every single step.

That's all for now friends. Hope we made the concepts of Ages easy now. Feel free to use the comments box below to reach us if you  have any doubts. We will answer. All the best and happy reading :)

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92 comments:

  1. Excellent Post. I don't know who is writing these articles. But please tell that guy that he is going to be a best teacher. God bless team :)

    ReplyDelete
  2. Thank you very much ............... :) :)

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  3. Whenever I was writing any bank clerk exam ssc exam I am always facing difficulty with age related problems some time I left these problems.But this article help to me solve age related problem with easy & quickly.Thank thank u very much...

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  4. does the average of the ages increase by 1 for every year

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    Replies
    1. Yep friend it does. Assume any number of people may be there. Obviously their age increases at the same time right? So does the average. 1 for every year.

      Delete
  5. these questions are so goooooooooood

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  6. thankyou very much mam please put some more shortcuts in reasoning and aptitude

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  7. Plz ...also menstion question n short cut method regarding ...time n work ....time n distance

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  8. Very good and easy to undertand.Thnx

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  9. nice work done by u ppl..........

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  10. Thank you very much explanations are very easy to understand

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  11. Now i feel comfortable for every age problem .

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  12. Thanks u admin,its very helpful for me....:)

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  13. thanks you.....:)

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  14. Thanks a lOT..... Unbeliveable help....... struggled alot many time in various exams.......

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  15. really superb article. May god bless you

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  16. thanku admin,it waz of great help :)

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  17. Thank u .. gud work...

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  18. very helpful.thanku :)

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  19. thanksfor helping us solving the problems .we dont c ur face bt pray god for ur betterment always.

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  20. awsum tricks..thank u so much..it helps a lot...





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  21. really its very useful and time consuming


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  22. u r genius.... from where u have studied friend

    ReplyDelete
  23. Really awesome work guys...keep it up

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  24. can i get sum more examples on ds topic?

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  25. time before i read this artical i never understand the concept of age problems , its really helpful thanks alot

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  26. Gud work...thanks for ur hard work

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  27. tq sooo v much..its really helpful..can u pls post for deductions too???

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  28. My goodness..this tricks are awesome!!!

    ReplyDelete
  29. Its a nice job done by u thank u very much

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  30. really appreciate your work !!! Not only this but all posts of yours all excellent.

    ReplyDelete
  31. gd job........really helps a lot......thanku

    ReplyDelete
  32. very easy to understanding,thank you very much.

    ReplyDelete
  33. Thankyou ........its very helpful!!!!!

    ReplyDelete
  34. Thank you........its very helpful!!!!!!!!

    ReplyDelete
  35. Instead of lots of Thanks ,you all guys should ask something to enhance your knowledge

    ReplyDelete
  36. Thanks its easily gone in mind. really gud work. may god bless you guys for this help for us

    ReplyDelete
  37. No doubt this is a wonderful and mind clearing post but is this sufficient for the problems of ages or there is few more concepts on age...????????

    ReplyDelete
  38. No doubt this is a wonderful and concept clearing post for the problems on ages but is this sufficient for such problems or there is some other concepts for it...?????????????

    ReplyDelete
  39. It was easy to understand the types and tricks to resolve

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  40. excellent work.....................going to be fan of this page

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  41. excellent work...........going to be fan of this page

    ReplyDelete
  42. Thanks alot for u people ...now I got the clear idea about on ages problems .....

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  43. Qus no 4: Anand and Milind age 4:7 after 6 year will be 7:10 what is theh milind age at present ?
    shortcut is
    difference 7:10 - 4:7=3:3 so 3=6 then 1=2
    milind age 7*2=14 and anand age 4*2=8

    ReplyDelete
  44. Reena is twice as old as Sunita. Three years ago, she was three times as old as Sunita. How old is Reena now ? answer is 12

    but when i'm applying the shortcut (new age diff * added or sub value)/ cross multiply of new and old ratio
    i get x=3 but it should be 6.... TO ADMIN G BATAIYE HUM KYA KAREIN...N ISS BAAR PLZZ REPLY KARNA COMMNET KO HIDE MAT KARNA..

    ReplyDelete
    Replies
    1. it is given 3 years ago so value of x 3 years ago is given by x=(2-1)*3/(3-2)=3 =>age of reena 3years ago will be 3*3 which gives 9 so present age will be 9+3=12..

      Delete
    2. Now, Reena: Sunita = 2x: x
      Three years ago, 3x: x

      So,
      New ratio difference= (3-1)=2
      Substracted no.=3
      Difference between old & new ratio's cross multiplication= (3-2)=1

      Put the values in formula,
      x= 2*3/1=6

      Reena's present age= 2x= 2*6=12 years.. :)

      Delete
  45. I'm glad that i visited this page, you people are doing good job..thank you for you needy information...

    ReplyDelete
  46. Good Explanation.....nice Question....Thank you so much mam.....!

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  47. while solving the problems it felt we r in bollywood :P :P evry Problem had a Filmy Charecter Name :P :P

    ReplyDelete
    Replies
    1. Very true said....But I guess admin knows this way we can learn faster.! AS we all are keen to know our bollywood star's age. At least for me, it's best way to learn when u enjoy learning. !

      Delete
  48. Thanks a lot .....You are doing a great job by providing these tricks to all at free of cost....It is very good work for those people who can not bear a large amount of fee......................

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  49. Can u please check Question no 2.! I wonder Why others didn't notice that.
    Question says after 5 year theirs age difference becomes 12.
    So I guess According to question We have to add 5 with both girl's age i.e-
    5x +5- 8x+5=12
    Correct me if I'm wrong.!

    ReplyDelete
    Replies
    1. age diff remains same no matter after how many years...it was given to confuse you

      Delete
  50. @yuvraj
    as clearly mention in the solution that the difference remains constant between them.

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  51. thank u so much for explaing in easier way

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  52. really a nice page. easy to understand thank u so much

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  53. pls answer tis,the average age of a man and his son is 28 years,6 years hence the ratio of their age becomes 12:5,what is the present age of the son?

    ReplyDelete
    Replies
    1. 17x=2*28+2*6 =>17x=68 =>x=4 so son's age after 6 years will be 20 so his present age is 14.

      or

      (x+6)/(y+6)=12/5 and x+y=2*28
      =>(x+6+y+6)/(y+6)=(12+5)/5
      substitute x+y=2*28
      =>(56+12)/(y+6)=17/5
      cross multiplying we get y=14..

      Delete
  54. but if we gone through options den it easy naaa.....!!

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  55. Can we download these?

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  56. pls tell the shortcut for this type problems, The sum of the ages of a father & son is 45 yrs.Five years ago the product of their ages was 4 times the father age at the time. the present ages of the father & son

    ReplyDelete
  57. thank u sooooo much.......really helpful........

    ReplyDelete

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