Question

In an envelope there are some $5$ rupee notes and some $10$ rupee notes. Total amount of these notes together is $350rupees$. Number of $5$ rupee notes are less by $10$ than number of $10$ rupee notes. Then find the number of $5$ rupee and $10$ rupee notes.

Answer 1

Let x be the no.of notes of Rs 5 and y be the

no. of notes of Rs 10

Second. to the question

$5x+10y=350$

(or) $x+2y=70$...(1) $(÷5)$

Also, $x=y-10$ or $x-y=-10$...(2)

eqn (2) $-$ eqn (1) $\Rightarrow x-y-x-2y=-10-70$

$\Rightarrow -3y=-60$

$\therefore y=\frac{60}{3}=20$

Put $y=20$ in (1) we get $x+2\times 20=70$

$x=70-40=30$

$\therefore$ There are 30 roots of Rs 5 and 20

notes of Rs 10.