Question

Arjun's piggy bank contains two kinds of coins and two kinds of bills. there are twice as many $1 bills like $5 bills. the number of quarters is 1 more than three times the number of $5 bills. and the number of dimes is 7 less than the number of quarters. how many of each type of bill and coin does Arjun have if the total is $39.90?

Answer 1

• $5 bills x 5, $1 bills x 10, quarters x 16, dimes x 9

Explanation:

• $5 bills = x, total = 5x
• $1 bills = 2x, total = x
• Quarters = 3x + 1, total = 0.25(3x + 1)
• Dimes = 3x + 1 - 7= 3x - 6, total = 0.1(3x - 6)

Equation below as the sum, solve for x:

• 5x + 2x + 0.25(3x + 1) + 0.1(3x - 6) = 39.9
• 7x + 0.75x + 0.25 + 0.3x - 0.6 = 39.9
• 8.05x - 0.35 = 39.9
• 8.05x = 40.25
• x = 40.25/8.05
• x = 5

Number of each bill and coin:

• $5 bills = 5
• $1 bills = 2*5 = 10
• Quarters = 3*5 + 1 = 16
• Dimes = 3*5 - 6 = 9