One day, a deli sold a total of 39 hamburgers and hot dogs. The revenue from these sales was $137.35. The hamburgers were $3.87 each and the hot dogs cost $2.90 each.

Question

One day, a deli sold a total of 39 hamburgers and hot dogs. The revenue from these sales was $137.35. The hamburgers were $3.87 each and the hot dogs cost $2.90 each.
a) Write a mathematical expression for the number of burgers, x, and the number of hot dogs, y, sold that day. 
Answer:  
b) Write a mathematical expression for the amount of revenue from this day's sales. Use x for the number of burgers and y for the number of hot dogs. 
Answer:  
c) How many hot dogs did the store sell that day? (Include the word hot dogs in your answer). 
Answer:

PsyDAG · Accepted Answer

x = 39 - y

3.87x + 2.90y = 137.35

Substitute 39-y for x in the second equation and solve for y. Insert that value into the first equation to solve for x. Check by putting both values into the second equation.