SOLUTION: If you buy 7 hamburgers and 3 slices of pizza from Sizzler, you get $1 change from a $20 bill. If you buy 8 hamburgers and 2 slices of pizza, you get $0.50 back from a 20 dollar bi

Algebra ->  Human-and-algebraic-language -> SOLUTION: If you buy 7 hamburgers and 3 slices of pizza from Sizzler, you get $1 change from a $20 bill. If you buy 8 hamburgers and 2 slices of pizza, you get $0.50 back from a 20 dollar bi      Log On


   

Question 226055: If you buy 7 hamburgers and 3 slices of pizza from Sizzler, you get $1 change from a $20 bill. If you buy 8 hamburgers and 2 slices of pizza, you get $0.50 back from a 20 dollar bill. How much change would you get back from a $20 if you bought 3 slices of pizza and 5 hamburgers?
The equations that i came up with were
3x+5y=20
x+y=20
but it did not work!
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


Let represent the cost of a slice of pizza and let represent the cost of a hamburger.

7 hamburgers and 3 slices of pizza cost $19, i.e. the $20 you paid minus the $1 change. 8 hamburgers and 2 slices of pizza cost $19.50. So:



and



Solve the system for the values of and . Multiply by 3 and multiply by 5, then add the two products. Subtract the sum from $20 for your answer.

John