Answer: They can practice the mermaid scene 5 full times.
Step-by-step explanation:
Hi, to answer this question we have to write an inequality.
So, the product the number of pirate scenes (4) and the time that each pirate scene takes(13), plus the product of the number of mermaid scenes (x) and the time that each mermaid scene takes (7) must be less or equal than 90 (minutes).
4(13) + 7x≤90
Solving for x
52+7x≤90
7x≤90-52
7x≤38
x≤38/7
x≤5.42
x≤5 times (rounded, since they are full scenes)