The pile contains 17 quarters and 15 half-dollars.
Let <em>x</em> = the number of quarters and <em>y</em> = the number of half-dollars.
We have two equations:
(1) $0.25<em>x</em> + $0.50<em>y</em> = $11.75
(2) <em>x</em> = <em>y</em> +2
Substitute the value of <em>x</em> from Equation (2) into Equation (1).
0.25(<em>y</em>+2) + 0.50<em>y</em> = 11.75
0.25<em>y</em> + 0.50 + 0.50<em>y</em> = 11.75
0.75<em>y</em> = 11.75 – 0.50 = 11.25
<em>y</em> = 11.25/0.75 = 15
Substitute the value of <em>y</em> in Equation (2).
<em>x</em> = 15 + 2 = 17
The pile contains 17 quarters and 15 half-dollars.
<em>Check</em>: 17×$0.25 + 15×$0.50 = $4.25 + $7.50 = $11.75.
