Hi Tracey B.,
Let x = the number of seats in the theater.
When the theater is half full, (1/2)x = the half full theater.
When the theater is one third full, (1/3)x = the one third full theater.
When 24 people leave the half full theater, (1/2)x - 24 = one third full theater, (1/3)x.
We have the equation:
(1/2)x - 24 = (1/3)x
Can you solve for x from here?
I have x = 144 seats in the theater.
I hope this helps, Joe.

David W.
Check: 72 - 24 = 48, which is 1/3 of 144 !!02/03/20