18.Lupe and her friends spent $20 on snack mix and water. They bought x bags of snack mix and y bottles of water. They bought a total of 11 items. The system of equations can be used to determine how many of each item they bought.

bags of snack = x = 6

bottles of water = y = 5

Step-by-step explanation:

The system of equations can be used to determine how many of each item they bought.

20.00=2.50x+1.00y

11=x+y

how many bags of snack mix did they buy?

Let

bags of snack = x

bottles of water = y

20.00 = 2.50x + 1.00y (1)

11 = x + y (2)

From (2)

x = 11 - y

Substitute x = 11 - y into (1)

20.00 = 2.50x + 1.00y

20.00 = 2.50(11 - y) + 1.00y

20.00 = 27.5 - 2.50y + 1.00y

20.00 - 27.5 = -2.50y + 1.00y

-7.5 = -1.5y

y = -7.5/-1.5

y = 5

Substitute y = 5 into (2)

11 = x + y

11 = x + 5

11 - 5 = x

x = 6

bags of snack = x = 6

bottles of water = y = 5