Question

The stock of grain in a government warehouse lasts 30 days for 4000 people . How many days will it last for 6000 people ?

Answer 1

Let $1$ person consume 'x' food in $1$ day

$1$ person $1$ day $\to$ x

$4000$ people $1$ day $\to 4000x$

$4000$ people $30$ days $\to 4000x\times 30$

Total food $=4000x\times 30$

Let no. of days be y

$6000$ people, $1$ day $\to 6000x$

$6000$ people, y days $\to 6000xy$

Total food $=6000xy$

So $4000x\times 30=6000xy$

$y=\frac{4000\times 30}{6000}$

$y=20$days.