Algebra
posted by Megan Brown on .
You have a piggy bank containing a total of 85 coins in dimes and quarters. If the piggy bank contain $14.50, how many dimes are there in the piggy bank?
Interest=principal multiply Rate multiply 1, or interest=principal multiply rate.

d = number of dimes
.10d = value of dimes
85  d = number of quarters
.25(85  d) = value of quarters
0.10d + .25(85  d) = 14.50
Solve for d, number of dimes
85  d = number of quarters