Question

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

• A. $2.5$ m
• B. $1.5$ m
• C. $1$ m
• D. $2$ m

Answer 1

The correct option is A $2.5$ m

Volume of the earth dugout

$\pi r^{2}h=\frac{22}{7}{\left(\frac{7}{2}\right)}^2\left(20\right)$

$=22\times 7\times 5=770m^3$

Area of the platform $=22\times 14=308m^2$

$\therefore$ Height of the platform $=\frac{770}{308}=\frac{5}{2}=2.5m.$