Question

A bag contains 77 coins consisting of quarters and nickels. The total value of the coins is $13.05. Which system of equations can be used to determine the number of quarter, q, and the number of nickels, n, in the bag?

Answer 1

q= quarters

n = 5-cent coins

77 coins for a total of $13.05

q+n=77

25q+5n=1305

per substitution :

q= 77-n

25(77-n)+5n=13,05

1925-25n+5n=13,05

-20n= 1305-1925

n=31

31 pieces of 5cents

77-31 = 46 pieces of 25cents

Explanation: