Question

Chang has 36 coins, all dimes and half-dollars. The total value of all these coins is $12.00. How many dimes does he have?

6
21
15
18

Answer 1

The first thing we must do for this case is to define variables.
We have then:
x = number of dimes
y = number of half-dollars
We write the system of equations:
x + y = 36
0.10x + 0.50y = 12
Solving the system we have:
x = 15
y = 21
Answer:
He has 15 dimes