Question 1026972: If I have 78 coins of all nickel and dimes and the value is $6.20. How many nickels and how many dimes do I have? Answer by Cromlix(4381) (Show Source):
You can put this solution on YOUR website! Hi there,
I have 78 coins of all nickel and dimes.
Make nickels = x
Make dimes = y
x + y = 78.......(1)
the value is $6.20
5x + 10y = 620...(2)
.........
x + y = 78.......(1)
5x + 10y = 620...(2)
Multiply Eq(1) by 10
10x + 10y = 780...(1)
5x + 10y = 620....(2)
Subtract Eq(2) from Eq(1)
5x = 160
x = 32
Substitute x = 32 into Eq(1)
x + y = 78
32 + y = 78
y = 78 - 32
y = 46
You have 32 Nickels
and 46 Dimes.
Hope this helps :-)
