Question

If $12$ boys earn $Rs.840$ in $7$ days, how much will $15$ boys earn in $6$ days?

Answer 1

Earning of $12$ boys in $7$ days $=Rs.840$

$\Rightarrow$ Earnings of $12$ boys in $1$ day $=Rs.$ $\frac{840}{7}$ $=Rs.120$

$\Rightarrow$ Earnings of $1$ boy in $1$ day $=Rs.$ $\frac{120}{12}$ $=Rs.10$

$\Rightarrow$ Earnings of $1$ boy in $6$ days$=Rs.$ $10\times 6=Rs.60$

$\Rightarrow$ Earnings of $15$ boys in $6$ days $=Rs.60\times 15=Rs.900$

Hence, $15$ boys will earn $Rs.900$ in $6$ days.