Question 776945: A collection of 40 dimes and quarters has a value of $6.40. How many of each coin type are in the collection? Answer by FrankM(1040) (Show Source):
You can put this solution on YOUR website! 10D + 25Q = 640 (you see that a dime is 10 cents, and quarter, 25 cents)
D + Q = 40 (there are 40 coins)
Multiply both sides of second equation by -10 to get
-10D - 10Q = -400 and add to first equation
0D + 15Q = 240
Q = 16
D = 40-16 = 24
16 quarters are $4.00
24 dimes are $2.40
$6.40 total
