Question

A sum Rs.$500$ is in the form of denominations of Rs.$5$ and Rs.$10$. If the total number of notes is $90$ find the number of notes of each denomination.
(Hint: let the number of $5$ rupee notes be '$x$', then number of $10$ rupee notes $=90-x$)

Answer 1

Let the number of 5 rupee notes be $x$,then

The number of 10 rupee notes =$90-x$

Then ,according to the question

$5x+10(90-x)=500$

$5x+900-10x=500$

$5x=400$

$x=80$

There are $80$ notes of Rs.$5$ and $10$ notes of Rs.$10.$