Question

A bill for Rs.$40$ is paid by means of Rs.$5$ notes and Rs.$10$ notes. Seven notes are used in all. If $x$ is the number of Rs.$5$ notes and $y$ is the number of Rs.$10$ notes, then

• A. $x+y=7$ and $x+2y=40$
• B. $x+y=7$ and $x+2y=8$
• C. $x+y=7$ and $2x+y=8$
• D. $x+y=7$ and $2x+y=40$

Answer 1

The correct option is B $x+y=7$ and $x+2y=8$

Given that there are $x$ number of Rs $5$ and $y$ number of Rs $10$ notes and total note for bill is seven

Then $x+y=7$ ............ (1)

The amount of bill is Rs $40$ paid

So, total value of Rs $5$ notes $=5x$ Rs

And total value of Rs $10$ notes $=10y$ Rs

Then $5x+10y=40$

Or $x+2y=8$ ........... (2)

$x+y=7$ and $x+2y=8$