Answer: They would paint 36 props in 3 hours.
Step-by-step explanation:
Given: The squad painted 18 props in 90 minutes.
Time taken to paint each prop = [tex]\dfrac{90\text{ minutes}}{18}[/tex]
= 5 minutes
Now, 1 hour = 60 minutes
3 hours = 3 x 60 minute = 180 minutes
Total props painted in 3 hours = (180 )÷5
= 36
Hence, with same rate , they would paint 36 props in 3 hours.