Answer:
1/5 = 20% not occupied.
Step-by-step explanation:
There are 72 occupied seats out of 90 total seats. We can say that there are 18 empty seats (90 - 72 = 18).
So there are 18 out of 90 seats occupied. We can rewrite that as 18/90. 18/90 simplifies to 9/45 = 3/15 = 1/5 = 20%.
As such, 20% of the seats are not occupied.
