A 15 m deep well with radius 2.8 m is dug and the earth taken out from it is spread evenly to from a platform of breadth 8 m and height 1.5 m. What will be the length of the platform? $$\left( {{\text{Take }}\pi = \frac{{22}}{7}} \right)$$

$$\eqalign{ & {\text{Volume of well}} = \pi {r^2}h \cr & = \frac{{22}}{7} \times {2.8^2} \times 15 \cr & {\text{Volume of platform}} = 8 \times 1.5 \times x \cr & {\text{Volume of platform}} = {\text{Volume of well}} \cr & 8 \times 1.5 \times x = \frac{{22}}{7} \times 2.8 \times 2.8 \times 15 \cr & x = 30.8{\text{ m}} \cr} $$