Question

A housing society consisting of $5500$ people needs $100L$ of water per person per day. The cylindrical supply tank is $7m$ high and has a diameter $10m$. For how many days will the water in the tank last for the society?

Answer 1

Total number of people $=5500$
Water required per person per day $=100L$

Total requirement of water by $5500$ peoples
$=100\times 5500=550000L$

Height of the cylindrical tank $=7m$
Diameter of the cylindrical tank $=10m$

$\therefore$ Radius $=5m$ $[\because \frac{diameter}{2}=radius]$

$\therefore$ Volume of cylinder $=\pi r^{2}h=\frac{22}{7}\times 5\times 5\times 7$
$=22\times 25=550m^3$
$=550\times 1000=550000L$ [$\because 1m^3=1000L$]

$\Rightarrow \text{Time taken to empty the water tank}$

$=\frac{\text{Total capacity of water tank}}{\text{Total requirement of water}}$

$=\frac{550000L}{550000L/day}$

$=1day$

Therefore, in the society, the water in the tank will last for $1$ day.