Question

A school provides milk to the students daily in a cylindrical glasses of radius $k$ cm. If the glass is filled with milk upto an height of $12$ cm, then litres of milk is needed to serve $1600$ students is $739.2l$.Find the value of $2k$.

Answer 1

Volume of milk in one cylindrical glass $=\pi \times r^2\times h=\pi \left(k{)}^2\right(12){cm}^3=\frac{22}{7}(k{)}^2\times 12=37.7k^2{cm}^3$
For $1600$ students, $V=1600\times \frac{22}{7}\times 12\times k^2=739.2\times 1000$

$k^2=\frac{739200\times 7}{22\times 1600\times 12}{cm}^2$

$\Rightarrow k=3.5$ cm $=\frac{7}{2}$ cm
$\Rightarrow k=7$