SOLUTION: A coin bank contains $17.00 in pennies and nickels. If there are 1140 coins in the bank, how many of the coins are nickels? I just cant seem to get a formula that works at all, of

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: A coin bank contains $17.00 in pennies and nickels. If there are 1140 coins in the bank, how many of the coins are nickels? I just cant seem to get a formula that works at all, of      Log On


   

Question 129290: A coin bank contains $17.00 in pennies and nickels. If there are 1140 coins in the bank, how many of the coins are nickels?
I just cant seem to get a formula that works at all, of course i have no clue how to get a formula for a problem like this, or i wouldnt be here. Please help!!! From "holt Algebra 1"
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
p+n=1140 or p=1140-n
.01p+.05n=17
.01(1140-n)+.05n=17
11.4-.01n+.05n=17
.04n=17-11.4
.04n=5.6
n=5.6/.04
n=140 the number of nickels.
1140-140=1000 pennies.
proof:
.01*1000+.05*140=17
10+7=17
17=17