movie theatre A has a popcorn machine with a 120 gallon capacity. it sells galllons of popcorn per hour. movie theatre B has a popcorn machine with a 150 gallong capacity. it sellls 9 galllons 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 - 7x = 150 - 9x ; x = 10
120 - 7x = 150 - 9x ; x = 15
120x - 7 =-840 150x - 9 ; x = 15
120 + 7x = 150 + 9x ; x = -15

1 answer

Let's analyze the problem step by step.

We want to find out when the amount of popcorn left in both machines will be the same. We'll denote \( x \) as the number of hours that pass.

  1. The amount of popcorn left in Theatre A after \( x \) hours: \[ \text{Remaining popcorn in A} = 120 - 7x \]

  2. The amount of popcorn left in Theatre B after \( x \) hours: \[ \text{Remaining popcorn in B} = 150 - 9x \]

Next, we set these two expressions equal to each other to find out when the amounts are the same: \[ 120 - 7x = 150 - 9x \]

Now, let's solve this equation for \( x \).

  1. Start by rearranging the equation: \[ 120 - 7x = 150 - 9x \]

  2. Add \( 9x \) to both sides: \[ 120 + 2x = 150 \]

  3. Now, subtract \( 120 \) from both sides: \[ 2x = 30 \]

  4. Finally, divide by \( 2 \) to solve for \( x \): \[ x = 15 \]

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

So the correct equation from the options provided is:

Correct Option:

  • 120 - 7x = 150 - 9x ; x = 15