a student makes a $10.25 purchase at the bookstore with $20 bill. The store has no bills and gives the change in quarters and fifty -cent pieces. There are 30 coings in all. How many of each kind are there?

how many quarters are there in the change? ___

how many fifty-cent pieces are there in the change?___

1 answer

Let h = # half dollars (50-cent pieces).
and q = # quarters.
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h+q=30
0.50*h + 0.25*q=20.00-10.25

Two equations. Two unknowns. Solve for h and q.