How do I find this answer?

Question

Tony and some friends went to the movies. They bought 4 drinks and 2 tubs of popcorn and spent a total of $32.50 on the food.  Each drink costs $3.50 less than a tub of popcorn.

 

 

 

Define a variable.

Write an equation that can be used to find the cost of one tub of popcorn.

Solve the equation to find the cost of a tub of popcorn.

Answer 1

Let price of drink be x

price of tub y

You have 4x+2y=32.5 (1) and

x = y -3.5                 (2)

 

Plug for x from (2) into (1):

4(y-3.5) + 2y = 32.5

4y -14 +2y = 32.5

6y = 14+32.5

y = (46.5)/6 = $7.75 the price of tub

x= y-3.5 = 7.75 - 3.5 = $4.25