Question 965860
x = number of $1 bills
y = number of $5 bills


x + y = 27
x + 5y = 75


Multiply equation 1 by 5.


5x + 5y = 135
x + 5y = 75


Subtract to get 4x = 60 and x = 15.


You need 15 one-dollar bills and 12 five-dollar bills.