Answer:
The average rate of speed of the model airplane, per second is 18 feet.
Step-by-step explanation:
Given:
It took the model airplane 5 seconds to go 90 feet.
Now, to find the average rate of speed in feet per second.
So, in 5 seconds the airplane go to = 90 feet.
In 1 second the airplane go to = 90 ÷ 5 feet.
Therefore, by dividing 90 feet by 5 seconds we get = 18 feet.
Thus, the average rate of speed of the model airplane, per second is 18 feet.