Answer :
Final answer:
The average rate at which the truck bed is being filled with sand between two and four minutes is 55 pounds per minute.
This is calculated by subtracting the weight of sand at two minutes (128 pounds) from the weight at four minutes (238 pounds) and then dividing the result by the time interval (2 minutes).
Explanation:
The truck contains 238 pounds of sand at four minutes and 128 pounds of sand at two minutes.
Therefore, subtracting the two amounts of sand gives us the total amount of sand added in those two minutes:
- 238 pounds - 128 pounds = 110 pounds
Since this amount was added over the course of two minutes (from minute two to minute four), we divide the total amount of sand added by the total time in minutes to find the average rate:
- 110 pounds / 2 minutes = 55 pounds per minute
So, the average rate at which the sand is filling the truck is 55 pounds per minute between two and four minutes.