Mental Maths Questions and Answers: Comparing Quantities | Mental Mathematics for Class 8 PDF Download

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QUESTIONS 
1. Find ?? , if ?? , ?? , ?? , ?? are in proportion. 
2. Convert 7:8 into percentage. 
3. If ???? % ???? ?????? = ???? % ???? ?? , find ?? . 
4. Out of `750, I saved 20%. Find my spending.  
5. In a gathering 87
?? ?? % people are standing. Find the percentage of people not 
standing.  
6. Express 12.5% as a ratio.  
7. Find ?? , if ?? % ???? ???? = ?????? . 
8. If 25% of a number is 148, find the number. 
9. Express 1.234% as a decimal. 
10. 105 chocolates are distributed between Pooja and Anupama in the ratio 2:3. How 
many chocolates will Anupama get? 
11. Salma bought a car for  `50000 and sold it for  `60000. Find her profit percent. 
12. If ?? % ???? ?????? + ???? % ???? ?? + ???? = ?????? , find the value of ?? . 
13. In an examination, a student has to score 40% marks to pass. He gets 65 marks 
and fails by 15 marks. Find the maximum number of marks. 
14. 60% of 30 students are good in mathematics, how many are not good in it? 
15. If ???? % ???? ?? = ???? then find y. 
16. Find ???? % ???? ` 1200. 
17. A shopkeeper buys a toy for `2500 and sell it for ` 3000. Find his gain and gain %. 
18. How much is 2% of 300 kilogram? 
19. Find (???? % ???? ?????? ) - (???? % ???? ?????? ). 
20. Express 174% as a fraction. 
21. Convert (?? . ?????? + ?? . ?????? ) into percentage. 
22. Sonam's present salary is `35000. She gets an increment of 10%, find her new 
salary. 
23. Find ?? . ?? % ???? ?????? . 
24. If 75% of a number is added to 150, the result is the number itself. Find the 
number. 
25. The cost of 6 pens is  ` 72. Find the cost of 9 such pens. 
26. Convert 
????
????
 into percentage. 
Page 2


  
 
QUESTIONS 
1. Find ?? , if ?? , ?? , ?? , ?? are in proportion. 
2. Convert 7:8 into percentage. 
3. If ???? % ???? ?????? = ???? % ???? ?? , find ?? . 
4. Out of `750, I saved 20%. Find my spending.  
5. In a gathering 87
?? ?? % people are standing. Find the percentage of people not 
standing.  
6. Express 12.5% as a ratio.  
7. Find ?? , if ?? % ???? ???? = ?????? . 
8. If 25% of a number is 148, find the number. 
9. Express 1.234% as a decimal. 
10. 105 chocolates are distributed between Pooja and Anupama in the ratio 2:3. How 
many chocolates will Anupama get? 
11. Salma bought a car for  `50000 and sold it for  `60000. Find her profit percent. 
12. If ?? % ???? ?????? + ???? % ???? ?? + ???? = ?????? , find the value of ?? . 
13. In an examination, a student has to score 40% marks to pass. He gets 65 marks 
and fails by 15 marks. Find the maximum number of marks. 
14. 60% of 30 students are good in mathematics, how many are not good in it? 
15. If ???? % ???? ?? = ???? then find y. 
16. Find ???? % ???? ` 1200. 
17. A shopkeeper buys a toy for `2500 and sell it for ` 3000. Find his gain and gain %. 
18. How much is 2% of 300 kilogram? 
19. Find (???? % ???? ?????? ) - (???? % ???? ?????? ). 
20. Express 174% as a fraction. 
21. Convert (?? . ?????? + ?? . ?????? ) into percentage. 
22. Sonam's present salary is `35000. She gets an increment of 10%, find her new 
salary. 
23. Find ?? . ?? % ???? ?????? . 
24. If 75% of a number is added to 150, the result is the number itself. Find the 
number. 
25. The cost of 6 pens is  ` 72. Find the cost of 9 such pens. 
26. Convert 
????
????
 into percentage. 
  
 
27. Ramesh got 450 marks out of 500. Find his percentage of marks. 
28. Find the difference between a paisa and 1% of a rupee. 
29. If ???? % ???? ?? + ?????? = ?????? then find the value of ?? . 
30. What is the resultant discount which is equal to (50%+20%) discount? 
31. Pushpa bought a shirt for ` 250, a frock for ` 350 and a pair of jeans for `650. 
She paid  
` 1000 for all. How much discount did she get? 
32. Evaluate ???? % ????  ` 5000 + ???? % ????   ` 1000 - ???? % ????  ` 6000. 
33. Find the difference between simple interest and compound interest for the sum 
of ` 2000 at the rate of 10% p. a. for 2 years. 
34. Find the difference between simple interest and compound interest for the sum 
of              ` 25700 at the rate of 10% p.a. for 1 year. 
35. What percent is  75 minutes of  2 hours? 
36. If an article was sold for ` 93, after a discount of ` 23.75. Find its marked price. 
37. The price of a computer is ` 25000. The sales tax charged is 12%. Find the 
amount that you will have to pay to buy it. 
38. The present value of a machine is ` 1000. Its value depreciates every year by 
10%. What will be its value after 2 years? 
39. Find the simple interest on ` 7000 for 3 years at the rate of 10% per annum. 
40. By selling a chair for ` 880, Rohan loses 20%. Find the cost price of the chair. 
41. Express 
(?? .?????? +?? .?????? )
?? .????
 as percent. 
42. Find gain or loss in percentage if CP =  ` 1600 and SP =  ` 1840. 
43. Amisha gets 70 marks in her exams which is 56% of the total marks. Find the 
maximum marks. 
44. Find ?? , if ???? % ???? ?? + ?? % ???? ???? + ???? = ?? 
45. An umbrella is sold at  ` 375, with a loss of 25%. What is its cost price? 
46. Find ?? , ???? ?? : ???? ? ?? : ??  
47. Find ???? % ???? ?????? + ???? % ???? ?????? 
48. Convert ?? . ?????? % into fraction. 
49. If 20% of 20% of x = 20, then find x. 
50. If 40% of a number is added to the number itself, it becomes 560. Find the 
number. 
  
Page 3


  
 
QUESTIONS 
1. Find ?? , if ?? , ?? , ?? , ?? are in proportion. 
2. Convert 7:8 into percentage. 
3. If ???? % ???? ?????? = ???? % ???? ?? , find ?? . 
4. Out of `750, I saved 20%. Find my spending.  
5. In a gathering 87
?? ?? % people are standing. Find the percentage of people not 
standing.  
6. Express 12.5% as a ratio.  
7. Find ?? , if ?? % ???? ???? = ?????? . 
8. If 25% of a number is 148, find the number. 
9. Express 1.234% as a decimal. 
10. 105 chocolates are distributed between Pooja and Anupama in the ratio 2:3. How 
many chocolates will Anupama get? 
11. Salma bought a car for  `50000 and sold it for  `60000. Find her profit percent. 
12. If ?? % ???? ?????? + ???? % ???? ?? + ???? = ?????? , find the value of ?? . 
13. In an examination, a student has to score 40% marks to pass. He gets 65 marks 
and fails by 15 marks. Find the maximum number of marks. 
14. 60% of 30 students are good in mathematics, how many are not good in it? 
15. If ???? % ???? ?? = ???? then find y. 
16. Find ???? % ???? ` 1200. 
17. A shopkeeper buys a toy for `2500 and sell it for ` 3000. Find his gain and gain %. 
18. How much is 2% of 300 kilogram? 
19. Find (???? % ???? ?????? ) - (???? % ???? ?????? ). 
20. Express 174% as a fraction. 
21. Convert (?? . ?????? + ?? . ?????? ) into percentage. 
22. Sonam's present salary is `35000. She gets an increment of 10%, find her new 
salary. 
23. Find ?? . ?? % ???? ?????? . 
24. If 75% of a number is added to 150, the result is the number itself. Find the 
number. 
25. The cost of 6 pens is  ` 72. Find the cost of 9 such pens. 
26. Convert 
????
????
 into percentage. 
  
 
27. Ramesh got 450 marks out of 500. Find his percentage of marks. 
28. Find the difference between a paisa and 1% of a rupee. 
29. If ???? % ???? ?? + ?????? = ?????? then find the value of ?? . 
30. What is the resultant discount which is equal to (50%+20%) discount? 
31. Pushpa bought a shirt for ` 250, a frock for ` 350 and a pair of jeans for `650. 
She paid  
` 1000 for all. How much discount did she get? 
32. Evaluate ???? % ????  ` 5000 + ???? % ????   ` 1000 - ???? % ????  ` 6000. 
33. Find the difference between simple interest and compound interest for the sum 
of ` 2000 at the rate of 10% p. a. for 2 years. 
34. Find the difference between simple interest and compound interest for the sum 
of              ` 25700 at the rate of 10% p.a. for 1 year. 
35. What percent is  75 minutes of  2 hours? 
36. If an article was sold for ` 93, after a discount of ` 23.75. Find its marked price. 
37. The price of a computer is ` 25000. The sales tax charged is 12%. Find the 
amount that you will have to pay to buy it. 
38. The present value of a machine is ` 1000. Its value depreciates every year by 
10%. What will be its value after 2 years? 
39. Find the simple interest on ` 7000 for 3 years at the rate of 10% per annum. 
40. By selling a chair for ` 880, Rohan loses 20%. Find the cost price of the chair. 
41. Express 
(?? .?????? +?? .?????? )
?? .????
 as percent. 
42. Find gain or loss in percentage if CP =  ` 1600 and SP =  ` 1840. 
43. Amisha gets 70 marks in her exams which is 56% of the total marks. Find the 
maximum marks. 
44. Find ?? , if ???? % ???? ?? + ?? % ???? ???? + ???? = ?? 
45. An umbrella is sold at  ` 375, with a loss of 25%. What is its cost price? 
46. Find ?? , ???? ?? : ???? ? ?? : ??  
47. Find ???? % ???? ?????? + ???? % ???? ?????? 
48. Convert ?? . ?????? % into fraction. 
49. If 20% of 20% of x = 20, then find x. 
50. If 40% of a number is added to the number itself, it becomes 560. Find the 
number. 
  
  
 
ANSWERS 
Question No. Answer Question No. Answer 
1 9 26 56% 
2 87.5% 27 90% 
3 500 28 0 
4 `  600 29 960 
5 12.5% 30 60% 
6 1:8 31 ` 250 
7 600 32 ` 3800 
8 592 33 ` 20 
9 0.01234 34 0 
10 63 35 62.5% 
11 20% 36 ` 116.75 
12 100 37 ` 28000 
13 200 38 ` 810 
14 12 39 ` 2100 
15 200 40 ` 1100 
16 ` 144 41 200% 
17 
Gain =  ` 500 
Gain% = 
20% 
42 
Gain% = 
15% 
18 6 kg 43 125 
19 60 44 300 
20 ?? ????
????
  45 ` 500 
21 14.8% 46 12 
22  ` 38500 47 125 
23 17.5 48         
?? ??????
 
24 600 49 500 
25 ` 108 50 400