Answer:
W(T)

Explanation:
The orignial weight of the truck is 11.25 and this remains a constant weight of the truck throughoout the loading of the sand. If the expression is written in terms of weight, we must convert the mass flow (ton/min) to weight in tons. This can be done by multiplying with time T minutes. The total weight after T minutes is the sum of the weight of the truck and the sand:
W(x)

W(T)
