Key with Explanations for Percentage Practice Problems

Friends, here are the answers with explanations for our Percentage Practice Problems. Please check the practice problems from here and try to solve on your own before checking these solutions. Happy Reading.
1. He saves Rs. 3534 which is 19% (100-81)

So, His monthly income (100%) is (100/19) x 3534 = Rs. 18600

Yearly income is 18600 x 12 = Rs. 223200

Important Note : Here we intentionally gave 18600 as the 1st answer option. In competitive exams we hurriedly choose the answer option as soon as we get a number which tallies with the given options. But here, we've asked about annual (yearly) income. Not monthly income. So, the answer will be 12 times 18600 i.e., Rs. 223200.  Beware friends, IBPS is more cunning than you think.

2. 42 - 28 = 14% = 210

59% value = (59/14) x 210 = 885

3. Let the numbers be X and Y

48% X = 36% Y

X/Y = 36/48

=> X:Y = 36:48 = 3:4

4. Let the third number be 100

So, First number = 100 + 30% of 100 = 130

and Second number
= 100 + 40% of 100 = 140

So, percentage of the first number to the second number = (130/140) x 100 = 92 (6/7)

5. Required percentage reduction is  (X/(100+-X)) x 100

here X is +20 (since Sugar price increased)

So, percentage reduction = (20/120) x 100 = 16(2/3)%

6. Let the first number be "X" and second number be "Y"

So, Y = (1/4) x 2400 = 600

(6/11) of X = 22% of 600 = 132

=> X = 132 . (11/6) = 242

So, 45% of 242 = 108.9

7. Let the price of the article be Rs. 10 and the number of articles be 10.

So, the revenue is 10 X 10 = Rs. 100

New price of the article is 80% of 10 = Rs. 8

New number of articles is 130% of 10 is 13

New revenue is Rs. 8 x 13 = Rs. 104

So, effect in the revenue is 104 -100 = Rs. 4

percentage effect is (4/100) x 100 = 4%

8. Ritu marks = 56% of 875

Smita marks = 92% of 875 = 805

Rina marks = 634

Total marks = 490 + 805 + 634 = 1929

So, Average marks = 1929/3 = 643

9. Total expenditure is 25% + 20% + 30% = 75%

Monthly savings is 100 - 75 = 25%, which is Rs. 3350

Monthly income is (100/25) x 3350 = Rs. 13400

So, Annual income is

12 x Rs. 13400 = Rs. 160800

10. Minimum marks required = 163 + 327 = 200

if 50 are the minimum marks then maximum marks = 100

here 200 are the minimum marks then maximum marks = (100 x 200) / 50 = 400

11. 40% - 25% = 7 - (-38)

=> 15% = 45

So, Total marks (100%) are (100/15) x 45 = 300

12. Sugar quality is 30 % of 8 = 2.4

Sugar quantity will be the same in the remaining solution as only water evaporates when boiled.

So, required percentage of sugar is

(2.4/6) x 100 = 40%

13. Milk quantity is 80% of 90 = 72 litres and water is 90 - 72 = 18 litres

after adding water, water will be 25% and milk will be 75%

As there is no change in the quantity of milk, 75% quantity is 72 litres

25% (water) quantity is (25/75) x 72 = 24 litres

Added quantity of water is 24-18 = 6 litres

14. Ruchika's monthly income = Rs. 32,000

so, Ravina's monthly income = 115% of 32000 = Rs. 36800

Ramola's monthly income = 3 x 36800 = Rs. 110400

So, Ramola's annual income = 12 x 110400

= Rs. 13,24,800

15. Let the population of the town 2 years ago was X

So, 115% of 90% of X = 12420

=> (115/100) . (90/100) . X = 12420

=> X = 12000

16. 32% + 70 = 350

= > 32% = 280

So, total marks (100%) = (100/32) x 280 = 875

17. Number of boys who failed is 25% of 800 = 200

Number of girls who failed is 20% of 600 = 120

Total number of students failed is 200 + 120 = 320

So, required percent is ((320 / (80 + 600)) x 100 = 22.86%

18. Akash's marks in subject "A" = 73

marks in subject "B" = 56% of 150 = 84

Total marks in all the three subjects

= 54% of 450 = 243

So, his marks in Subject "C" = 243 - (73+84) = 86

19. Let the number of males = "X"

then the number of females will be (6000 - X)

So, 8% of X + 10% of (6000-X) = 530

8X + 6000 - 10X = 53000

2X = 7000 = > X = 3500

20. Let the length be 10 and breadth also be 10.

So, Area = 10 x 10 = 100

New Length (10% excess) = 11

New Breadth (5% deficit) = 9.5

New area = 11 x 9.5 = 104.5

So, Change in area = 104.5 - 100 = 4.5

Percentage change = (4.5/100) x 100 = 4.5%

21. The required % = ((25 / (100-25)) x 100 = 33(1/3)%

22. 115% of 92% of 132

(115/100) x (92/100) x 132 = 139.656

1. really good for ever

2. Thanku sir
Superb Explanation

3. thank u mam:)

4. hi....gud eve

5. ya i selected option 1, 18600 ithout noticing annual income is aked, then corrected it

6. gud evening ..

7. q.5 i think ans is 25% plz check.. frnds reply for dat question

8. pls see on explanation post..

10. Thanx sir ...great explanation....once again thanx....

11. thnk u so much sir....

12. sir i think ther is a mistake in qstn 19...

13. Good approach

14. sir i think there is a mistake in qstn 19...plzz chekk...

15. Thank You :)

16. Last year my CWE PO-3 exam was on 19th november 2013(Odisha)...The supercyclone philine came & destroyed everything till 16th october & we the people of Odisha got electricity till 16th evening...Similar the case this year also(Cyclone "Hudhud")...I don't know why we the aspirants of Odisha suffer each year ???

17. check once more.. i got 16(2/3)

20-C-(20*C/100)=0
100-5C-C=0
100=6C
C=16(2/3)

Since consumption reduced C is taken as negative
Actual formula is a+b+(ab/100)
Since there is no change in exp it is equated to zero

18. Please provide test for data interpretation

19. Haha...can understand

20. simple method :-
120-->20
100-->??
120/20-6
100/6-16(2/3)...

21. simple method :-

120-->20

100-->??

120/20-6

100/6-16(2/3)..

22. yaa seen thanks :)

23. 18600*12 =annual

24. q 19 males increases by 8%.so x*108/100 will come .I can't understand that problem.please help me

25. question 9 ans is 170800

26. i have doubt in 20 th prob.its mentioned in question that its rectangle...can v take 10*10..length =breadth ?????

27. taking 10 is easy for calculation

28. why there is a waiting for approval before posting any comment. can anyone clarify this?

29. thanks a lot team :)

30. ty vidhya... but wnt it become square then???

31. 6530-6000=530;this 530is wat the added 8%of male and 10%of female;
so 8%of male +10%female=530;female=6000-male;re

32. can some one explain me 21 st question

33. same with me.Last year my exam was on 19th october and this year 12th october.

34. Vidhya Indira lekshmiOctober 9, 2014 at 11:41 AM

no, it is percentage increase

35. 28/40

36. thanks mam it is very usefull

37. share marketing specialization pdf for ibps SO

38. Hello Gr8ambitionz TEAM plz plz plz plz provide capsule for IT OFFICER ..

39. Super explanation sir