Problema Solution
a student makes $10.50 purchase at the bookstore with a $20 bill. the store has no bills and gives the change in quarters and fifty-cent pieces. there are 30 coins in all. how many of each kind are there?
Answer provided by our tutors
Let represent the number of quarters. Then, since there are 30 coins in all, there must be 50-cent pieces. The purchase was $10.50, so the change from $20.00 must be $9.50 or 950 cents.
Quarters are worth 25 cents, so quarters must be worth cents. Likewise, 50-cent pieces are worth...wait for it now...50 cents, so 50-cent pieces must be worth cents.
And finally:
25X +1500 -50X=950
-25X= 950-1500
X=550/25=22the number of quarters
50 CENTS =30-X= 8 FIFTY CENTS