SOLUTION: A vending machine will accept nickels and dimes only. The attendant checks the machine and finds 42 coins whose value is $3.40. How many coins of each type were there?

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Question 151577: A vending machine will accept nickels and dimes only. The attendant checks the machine and finds 42 coins whose value is $3.40. How many coins of each type were there?
Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!
Let x=nickels
y=dimes
so, x%2By=42, right? ----------------> eqn 1
Also, 0.05x%2B0.10y=3.40 ------------> eqn 2
in eqn we get, y=42-x, substitute in eqn 2 we have,
0.05x%2B0.10%2842-x%29=3.40
0.05x%2B4.2-0.10x=3.40
4.20-3.40=0.10x-0.05x
0.80%2F0.05=cross%280.05%29x%2Fcross%280.05%29 -----------> x=16, # of dimes
For # of nickels go back eqn 1:
16%2By=42, y=42-16=26, # of nickels
In doubt? Go back eqn 2;
0.05%2816%29%2B0.10%2826%29=3.40
0.80%2B2.60=3.40
3.40=3.40
Thank you,
Jojo