Question

There are some $20$ paise and some $25$ paise coins in a bag. The total number of coins is $50$ and the amount in the bag is $Rs.11.25$. Find the number of coins of each value in the bag by method of elimination?

Answer 1

Let no. of 20 paise coins is x and no. of 25 paise coins is y. Then by the given question,

$x+y=50$ (equation 1)

$20x+25y=1125$

or, $4x+5y=225$(equation 2)

Multiplying (1) with 4 we get,
$4x+4y=200$ (equation 3)

Subtracting (3) from (2) we get,
$y=25$

Putting in (1)

$x=50-y=50-25=25$

∴ $x=25,y=25$