Secondary School (English Medium) (5 to 8) Class 8 - CBSE Question Bank Solutions for Mathematics

Find the smallest square number that is divisible by each of the numbers 8, 15, and 20.

There are two cuboidal boxes as shown in the adjoining figure. Which box requires the lesser amount of material to make?

(a)	(b)

Daniel is painting the walls and ceiling of a cuboidal hall with length, breadth, and height of 15 m, 10 m, and 7 m, respectively. From each can of paint, 100 m² of area is painted. How many cans of paint will she need to paint the room?

Find the height of a cuboid whose base area is 180 cm² and volume is 900 cm³?

A cuboid is of dimensions 60 cm × 54 cm × 30 cm. How many small cubes with side 6 cm can be placed in the given cuboid?

Water is pouring into a cubiodal reservoir at the rate of 60 litres per minute. If the volume of the reservoir is 108 m³, find the number of hours it will take to fill the reservoir.

Carry out the following division:

28x⁴ ÷ 56x

Carry out the following divisions:

−36y³ ÷ 9y²

Carry out the following divisions:

66pq²r³ ÷ 11qr²

Carry out the following divisions:

34x³y³z³ ÷ 51xy²z³

Carry out the following divisions:

12a⁸b⁸ ÷ (−6a⁶b⁴)

If 21y5 is a multiple of 9, where y is a digit, what is the value of y?

If 31z5 is a multiple of 9, where z is a digit, what is the value of z? You will find that there are two answers for the last problem. Why is this so?

If 24x is a multiple of 3, where x is a digit, what is the value of x?

(Since 24x is a multiple of 3, its sum of digits 6 + x is a multiple of 3; so 6 + x is one of these numbers: 0, 3, 6, 9, 12, 15, 18…. But since x is a digit, it can only be that 6 + x = 6 or 9 or 12 or 15. Therefore, x = 0 or 3 or 6 or 9. Thus, x can have any of four different values)

If 31z5 is a multiple of 3, where z is a digit, what might be the values of z?

Write the additive inverse of each of the following rational numbers:

Write the additive inverse of each of the following rational numbers:

Write the additive inverse of each of the following rational numbers:

Write the additive inverse of each of the following rational numbers:

Write the negative (additive inverse) of each of the following: