Question

A collection of nickels, dimes, and quarters consist of 18 18 coins with a total of $ 2.05 $2.05. if the number of dimes is equal to the number of nickels, find the number of each type of coins.

Answer 1

The first thing we must do for this case is to define variables.
 We have then:
 x = the number of nickels
 y = the number of dimes
 z = the number of quarters
 We write the system of equations:
 0.05x + 0.1y + 0.25z = 2.05
 x + y + z = 18
 x = y
 Solving the system we have:
 x = 7
 y = 7
 z = 4
 Answer:
 nickels = 7
 dimes = 7
 quarters = 4