CBSE 2017 Board Paper

Class 10 Math - Set 3 - Q25. Volume of solids

Video Explanation

Area of roof = 22 m × 20 m
Let the rainfall be ‘x’ m.

Volume of rain fallen on roof in m3 = area of roof × rainfall in m
= 22 × 20 × x m3

Volume of rain water collected = volume of cylindrical tank

Diameter of cylinder = 2 m. So its radius = 1 m.
Height of cylinder = 3.5 m = $$frac{7}{2}$ m Volume of rain water collected in the cylinder = π r2 h = $\frac{22}{7}$ ×$1)(1) × $$frac{7}{2}$ Equating the two volumes. 22 × 20 × x = $\frac{22}{7}$ ×$1)(1) × $\frac{7}{2}$
x = $\frac{1}{40}$ m
Multiply by 100 to express x in cm. $\frac{1}{40}$ × 100 = 2.5 cm

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