Movie Theatre A has a popcorn machine with a 120-gallon capacity. It sells 7 gallons of popcorn per hour. Movie Theatre B has a popcorn machine with a 150-gallon capacity. It sells 9 gallons of popcorn per hour. Write and solve an equation to show when the two popcorn machines will have the same amount of popcorn left.

120 - 7t = 150 - 9t

2t = 30
t = 15

after 15 hours, they both will have the same amount of stale popcorn

Let's assume that x represents the number of hours passed since both popcorn machines started selling popcorn.

For Movie Theatre A, the amount of popcorn remaining after x hours would be 120 - 7x gallons.

For Movie Theatre B, the amount of popcorn remaining after x hours would be 150 - 9x gallons.

To find when the two popcorn machines will have the same amount of popcorn left, we set up the equation:

120 - 7x = 150 - 9x

Now, let's solve this equation:

120 + 2x = 150

2x = 150 - 120

2x = 30

x = 30 / 2

x = 15

Therefore, the two popcorn machines will have the same amount of popcorn left after 15 hours.

To solve this problem, let's first define some variables:

Let's call the number of hours passed since the popcorn machines started selling popcorn as "t".
Let P_A be the amount of popcorn left in Theater A's machine after t hours.
Let P_B be the amount of popcorn left in Theater B's machine after t hours.

We know that Theater A sells 7 gallons per hour, so the amount of popcorn left in Theater A's machine after t hours can be calculated as:
P_A = 120 - 7t (since the machine's initial capacity is 120 gallons)

Similarly, Theater B sells 9 gallons per hour, so the amount of popcorn left in Theater B's machine after t hours can be calculated as:
P_B = 150 - 9t (since the machine's initial capacity is 150 gallons)

To find the time when both machines have the same amount of popcorn left, we need to set P_A equal to P_B and solve for t:
120 - 7t = 150 - 9t

Adding 9t to both sides of the equation:
9t - 7t + 120 = 150

Simplifying the equation:
2t = 30

Dividing both sides of the equation by 2:
t = 15

Therefore, after 15 hours, both Movie Theater A and Movie Theater B will have the same amount of popcorn left.