Problema Solution
A collection of 30 coins worth $5.50 consists of nickels, dimes, and quarters. There are twice as many dimes as nickels. How many quarters are there?
Answer provided by our tutors
Let number of nickels = x
=> number of dimes = 2x
=> number of quarters = 30 - x - 2x = 30 - 3x
Total amount = 5.50
=> 0.05*x + 0.1*2x + 0.25*(30-3x) = 5.5
=> 0.05x + 0.2x +7.5x -0.75x = 5.5
=> -0.50x = -2
=> x = 4
=> nickels = 4
=> dimes = 8
=> quarters = 30 - 12 = 18