Question

Kennedy and Olivia go to the movie theater and purchase refreshments for their friends.

Kennedy spends a total of $77.50 on 12 bags of popcorn and 2 drinks.

Olivia spends a total of $51.00 on 3 bags of popcorn and 6 drinks.

Write a system of equations that can be used to find the price of one bag of popcorn and the price of one drink.

Using these equations, determine and state the price of a drink, to the nearest cent.

Answer 1

6x + y = 38.75

x + 2y = 17

price of drink is $5.75

Explanation:

Let the price of popcorn be x

Let the price of drink be y.

price of 12 bags of popcorn will be 12x

price of 2 drinks will be 2y

it is given that "Kennedy spends a total of $77.50 on 12 bags of popcorn and 2 drinks."

thus

12x + 2y = 77.50

dividing LHS and RHS by 2 we have

12x/2 + 2y/2 = 77.50/2

=> 6x + y = 38.75 _________(1)

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price of 3 bags of popcorn will be 3x

price of 6 drinks will be 6y

it is given that "Olivia spends a total of $51.00 on 3 bags of popcorn and 6 drinks."

thus

3x + 6y = 51.00

dividing LHS and RHS by 3 we have

3x/3 + 6y/3 = 51/3

=> x + 2y = 17 _____________(2)

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Thus we have two equation

6x + y = 38.75 _________(1)

x + 2y = 17

=> x = 17 - 2y

putting this value of x in equation 1 we have

6( 17 - 2y) + y = 38.75

=> 102 - 12y + y = 38.75

=> 102 - 11y = 38.75

=> -11y = 38.75 -102

=> -11y = -63.25

=> y = -63.25/-11 = 5.75

as we have x = 17 - 2y

using 5.75 in place of y

x = 17 - 2(5.75 )

=> x = 17 - 11.5

=> x = 5.5

Thus, system of equations are

6x + y = 38.75

x + 2y = 17

price of drink is $5.75