Question

Jacob opened his piggy bank and found Nickels, Dimes, and Quarters totaling 81 coins. The total value of the coins was $7.90. The number of Dimes was 7 less than triple the number of Quarters. Write a system of equations that represents this situation. Use N, D, and Q.

Answer 1

A Nickel is 5 cents = 5/100 = $0.05

A dime is 10 cents = 10/100 = $0.1

A quarter is 25 cents = 25/100 = $0.25

Let N represent the number of nickels

Let D represent the number of dimes

Let Q represent the number of quarters

Jacob opened his piggy bank and found Nickels, Dimes, and Quarters totaling 81 coins. It means that

N + D + Q = 81

The total value of the coins was $7.90. It means that

0.05N + 0.1D + 0.25Q = 7.9

The number of Dimes was 7 less than triple the number of Quarters. It means that

D = 3Q - 7

The system of equations is

N + D + Q = 81

0.05N + 0.1D + 0.25Q = 7.9

D = 3Q - 7