You have a piggy bank a total of 72 coins in dime and quarters . If the piggy bank contains 10.80 how many dime are in the piggy bank
Let the number of dimes = D
Then the numbers of quarters = 72 - D
So....we have this
Number of dimes * value each + Number of quarters * value each = total amount
D * .10 + (72 - D)* .25 = 10.80 simplify
.10D + 18 - .25D = 10.80
-.15D + 18 = 10.80 subtract 18 from each side
-.15D = -7.2 divide both sides by -.15
D = 48 (dimes)