# CBSE Class X Board Paper

Math Solutio - Set 3 - Q17. Mensuration

#### Video Explanation

Volume of solid iron cuboid = volume of hollow cylindrical pipe

Volume of solid iron cuboid = 4.4 × 2.6 × 1 m3 .......... (1)

Volume of hollow cylindrical pipe = volume of outer cylinder – volume of inner cylinder

Radius of outer cylinder = 30 + 5 = 35 cm = $$frac{35}{100}$m Radius of inner cylinder = 30 cm = $\frac{30}{100}$m Volume of the outer cylinder = π × $$$frac {35} {100}{$}^{2}) × h, where h is the length of the pipe. Volume of the inner cylinder = π × $$$frac {30} {100}{$}^{2}) × h Volume of the pipe = $\frac{πh}{$100$^2}) (352 – 302)
= $$frac{22h}{7 × 10,000}$$(35 + 30)(35 – 30))
= $$frac{22h}{7 × 10,000}$$65 × 5) m3 .......... (2)

Equating (1) and (2)
4.4 × 2.6 × 1 = $$frac{22h}{7 × 10,000}$$65 × 5)
Or h = $\frac{4.4 × 2.6 × 1 × 70,000}{22 ×65 ×5}$ = 112m

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