A diner makes vanilla milkshakes and chocolate milkshakes. The vanilla milkshake machine has a 300-cup capacity, and sells 15 cups per day. The chocolate milkshake machine has a 280-cup capacity, and sells 20 cups per day. Write an equation to show when the two machines will have the same amount of milkshake left. Use x as your variable

[_] - [_] × = [_] - [_x]

1 answer

To write an equation to show when the two machines will have the same amount of milkshake left, we can first express the amount of milkshake left in each machine as a function of time, represented by the variable \( x \), where \( x \) is the number of days.

  1. For the vanilla milkshake machine:

    • Initial capacity: 300 cups
    • Sells 15 cups per day
    • Amount left after \( x \) days: \[ 300 - 15x \]
  2. For the chocolate milkshake machine:

    • Initial capacity: 280 cups
    • Sells 20 cups per day
    • Amount left after \( x \) days: \[ 280 - 20x \]

To find when the two machines will have the same amount of milkshake left, we can set these two expressions equal to each other:

\[ 300 - 15x = 280 - 20x \]

This equation compares the remaining milkshake in both machines over time. Solving this will find the number of days \( x \) after which the milkshakes in both machines will be equal.

We can rearrange the terms as follows to fit your requested format:

\[ 300 - 15x = 280 - 20x \]

This can be interpreted as:

\[ 300 - 280 = 15x - 20x \]

Thus, you can structure your answer in the requested format:

\[ [300] - [20]x = [280] - [15]x \]

So:

  • \( [_] = 300 \)
  • \( [_] = 20 \)
  • \( [_] = 280 \)
  • \( [_] = 15 \)