Question

At the beginning of a month, a factory has enough materials to make $240$ tonnes of steel in a month. If $60$ more tonnes of steel is to be made that month, how long will the materials last?

Answer 1

In $30$ days steel manufactured $=240$ tonnes

Now, $60$ more tonnes of steel is to be manufactured in that month.

So,

$240+60=300$ Tonnes of steel to be manufactured in the month.

Therefore,

More steel manufactured, fewer days the material will last.

This is an inverse proportion.

$240:300::30:x$

$300x=240.30$

$300x=7200$

$x=\frac{7200}{300}$

$x=24$

So, the material will last for $24$ days.