One of the important question for the board exam class 10 from

mensuration chapter.This question is from r d sharma class 10 maths.

chapter-16.2 question number-7 maths r d sharma,mensuration.

In this question we have to find the volume

of water left in the tub. Consider a cylindrical tub having

radius as 5 cm and its length 9.8 cm. It is full of water. A solid

in the form of a right circular cone mounted on a hemisphere is

immersed in tub. If the radius of the hemisphere is 3.5 cm and the

height of the cone outside the hemisphere is 5 cm.

Given,

The radius of the Cylindrical tub (r) = 5 cm

Height of the Cylindrical tub (H) = 9.8 cm

Height of the cone outside the hemisphere (h) = 5 cm

Radius of the hemisphere = 3.5 cm

Now, we know that

The volume of the Cylindrical tub (V1) = Ï€r2H

V1 = Ï€(5)2 9.8

V1 = 770 cm3

And, the volume of the Hemisphere (V2) = 2/3 Ã— Ï€ Ã— r3

V2 = 2/3 Ã— 22/7 Ã— 3.53

V2 = 89.79 cm3

And, the volume of the Hemisphere (V3) = 23 Ã— Ï€ Ã— r Ã— 2h

V3 = 2/3 Ã— 22/7 Ã— 3.52 Ã— 5

V3 = 64.14 cm3

Thus, total volume (V) = Volume of the cone + Volume of the hemisphere

= V2 + V3

V = 89.79 + 64.14 cm3

= 154 cm3

So, the total volume of the solid = 154 cm3

In order to find the volume of the water left in the tube, we have to subtract the volume of the hemisphere and the cone from the volume of the cylinder.

Hence, the volume of water left in the tube = V1 â€“ V2

= 770 â€“ 154

= 616 cm3

Therefore, the volume of water left in the tube is 616 cm3.