Question

I have a total of Rs $300$ in coins of denomination $Re1,Rs2$ and $Rs5$. The number of $Rs2$ coins is $3$ times the number of $Rs5$ coins. The total number of coins is $160$. How many coins of each denomination are with me

Answer 1

Let number of $Rs5$ coins be $x$
Number of Rs $2$ coins $=3\times$ Number of $5$ Rs coins $=3x$
Number of $Re1$ coins $=160-(x+3x)$
$=160-4x$

Amount of $Rs5$ coins $=5\times x=5x$
Amount of $Rs2$ coins $=2\times 3x=Rs6x$
Amount of $Re1$ coins $=(160-4\times x)$
$=160-4x$

As per the question, Total amount $=Rs300$
$160-4x+5x+6x=300$
$7x=300-160$
$x=\frac{140}{7}$
$x=20$

Number of Re $1$ coins $=160-4x$

$=160-4\times 20$
$=80$

Number of $Rs2$ coins $=3x=3\times 20=60$
Number of $Rs5$ coins $=x=20$