Question

A 20 m deep well with diameter 7 m is dug and earth from digging is evenly spread out to form a platform 22 m by 14 m. The height of the platform is

• A. $2.3m$
• B. $2.5m$
• C. $3m$
• D. $2.7m$

Answer 1

Answer: (B)

$2.5m$

Let the height raised $=hm$

Equating volumes of cylindrical well and cuboidal platform
$22\times 14\times h=\frac{22}{7}\times {\left(\frac{7}{2}\right)}^2\times 20$
$h=2.5m$