Question

There are three stair-steps as shown in the figure below. Each stair-step has width $25cm$, height $12cm$ and length $50cm$. How many bricks have been used in it, if each brick is $12.5cm\times 6.25cm\times 4cm?$

Answer 1

Volume of one stair-step $=25\times 12\times 50$
$=15000c{m}^3$
Volume of one brick $=12.5\times 6.25\times 4$
$=312.5c{m}^3$
$\therefore$ Number of bricks made by one stair-step $=\frac{\text{Volume of one stair-step}}{\text{Volume of one bricks}}$
$=\frac{15000}{312.5}$
$=48$ bricks
$\therefore$ Number of bricks's made by three stair-step $=3\times 48$
$=144$ bricks