+47 Molly has eighty-six coins, all dimes or quarters, worth a total of $14.60. How many dimes does Molly have?
Define two variables and write a system of equations that represents the word problem. Use either substitution or elimination to solve and show all of your work.
+129852 Let D = the number of dimes and Q = the number of quarters
The system is
D + Q = 86
10D + 25Q = 1460
Rearrange the first equation as Q = 86 - D
Sub this into the second equation
10D + 25 ( 86 - D) = 1460 simplify
10D + 2150 - 25D = 1460
-15D = 1460 - 2150
-15D = -690
D = -690 / -15 = 46 dimes
And Q = 86 - 46 = 40 quarters
