Question

Jenny bought gallons of lemonade and milk for a banquet. A gallon of lemonade cost $5 and a gallon of milk cost $3 Jenny spent $120 and bought 32 total gallons how many gallons of milk did Jenny buy?

Answer 1

20 gallons of milk.

Step-by-step explanation:

Let the number of gallons of lemonade bought =x

Let the number of gallons of milk bought =y

Jenny bought 32 gallons in total, therefore:

`\begin{gathered} x+y=32 \\ \implies x=32-y \end{gathered}`

A gallon of lemonade cost $5 and a gallon of milk cost $3.

Jenny spent $120.

`5x+3y=120`

We solve the two equations simultaneously by substituting x=32-y into the second equation.

`\begin{gathered} 5x+3y=120 \\ 5(32-y)+3y=120 \\ 160-5y+3y=120 \\ -5y+3y=120-160 \\ -2y=-40 \\ y=(-40)/(-2) \\ y=20 \end{gathered}`

We see that Jenny bought 20 gallons of milk.