Question

One number is four times the other their sum is $80$. Find the smaller number.

Answer 1

Let one number be $x$
The other is $4x$
According to the question
Sum of the numbers $=80$
$\therefore$ $x+4x=80$
$\Rightarrow$ $5x=80$
$\Rightarrow$ $x=\frac{80}{5}$
$\Rightarrow$ $x=16$
The other number is $4x=4\times 16=64$
Hence, the required numbers are $16$ and $64$