Std 8 – Math Revision
1. Rationalize the denominator:
2. Which ratio is greater 4:5 or 19:25 ?
3. If 32 horses consume 112 kg of food in a certain period, how much food will be consumed
by 11 horses during the same period?
4. Express
in percentage
5. Simplify:
6. Factorise
7. Find the HCF & LCM of
and
8.
, make d as the subject. Also find d, when S=21, a =15 and n=7
9. Find two consecutive odd numbers such that two-fifths of the smaller exceeds two-ninths of
the larger by 4.
10. The base of a triangle is 36 cm and its corresponding height is 13 cm. Find the area of the
triangle.
11. Rationalize the denominator:
12. Find the ratio of each in the simplest form:
i.
240 m and
ii. Re 1 and 15 p
iii. 2 scores and 3 dozens
13. If the wages of 15 labourers for 6 days are Rs 8100, find the wages of 21 labourers for 5
days.
14. 7 workers working 6 hours a day can build a wall in 12 days. How many days will 3 workers
take to build a similar wall, working 8 hours a day?
15. Find
of 1.4 kg.
16. Simplify:
17. Factorise
18. Find the HCF & LCM of
and
19. The denominator of a fraction is 9 more than its numerator. If the numerator and the
denominator both are increased by 7, the new fraction becomes
. Find the original fraction
20. Find the area of a triangle whose sides are 28 cm, 21 cm and 35 cm. Also find the length of
the altitude corresponding to the largest side of the triangle.
21. Rationalize the denominator:
22. If a:b =
and b:c =
, find:
i. a:b:c ii. a:c
23. If 3 men or 4 women can earn Rs 360 in a day, find how much will 7 men earn and 9 women
earn in a day?
24. What per cent of 84 is 7?
25. Simplify:
26. Factorise
27. Solve:
28. The length of a rectangle is 12 m and its diagonal is 15 m. Find the breadth and area of the
rectangle.
29. Rationalize the denominator:
30. A certain sum of money is divided among A, B, C in the ratio 3:5:7. If B’s share is Rs. 150,
find the total amount and the share of each one of A and C.
31. A hostel had rations for 100 students for 40 days. After 4 days, 20 more students join hostel.
How long will the remaining ration last?
32. On decreasing a number by 18%, it becomes 779. Find the number.
33. Factorise
34. Solve by substitution method
35. A two digit number is 5 times the sum of its digits. If 9 is added to the number, its digits are
reversed. Find the number.
36. A rectangular grassy lawn measuring 38 m by 25 m has been surrounded externally by 2.5 m
wide path. Calculate the cost of gravelling the path at the rate of Rs 4.50 per sq. Metre.
37. Simplify:
38. Divide Rs 747 among A, B, C such that 4A = 5B = 7C
39. A can do a piece of work in 25 days and B can do it in 20 days. They work at it together for 5
days and then A goes away. In how many days will B finish the remaining work?
40. In an examination, 94% of the candidates passed and 33 failed. How many candidates
appeared?
41. Factorise
42. Find the perimeter, diagonal and area of a square having each side 8 m long. (take
)
43. In an election, there were only two candidates. The winner obtained 56% votes and won by
8400 votes. Find the total number of votes polled.
44. A number 4.0 is wrongly read as 4.48; find the percentage of error.
45. Simplify