laura has $87 one dollar bills and five dollar bills she has three more five dollar bills than one dollar bills how many of each does she have

Question

laura has $87 one dollar bills and five dollar bills she has three more five dollar bills than one dollar bills how many of each does she haaux8

Answer 1

laura has $87 in one dollar bills and five dollar bills. She has three more five dollar bills than one dollar bills. How many of each does she have?

Let N be the number of one dollar bills.

Let F be the number of five dollar bills.

Then,

N*1 + F*5 = 87     (this is all the money she has)

F = N + 3              (Number of five dollar bills is 3 more than the one dollar bills)

Substituting for F = N + 3 into the other eqn above,

N + (N + 3)*5 = 87

6N + 15 = 87

6N = 72

N = 12

F = 15