A bridge can hold a maximum of 75,000 pounds. A truck that weighs 40,000 pounds carries boxes that weigh 40 pounds each. What is the maximum number of boxes the truck can carry to cross the bridge? Express your answer as an inequality.
After the truck's weight is taken into account, the total weight of the boxes must not exceed 75,000 pounds. Thus, the inequality is $40n + 40,000 \leq 75,000$, where $n$ is the number of boxes the truck is carrying. We subtract 40,000 from both sides, getting $40n \leq 35,000$. Dividing both sides by 40, we get $n \leq 875$, so the maximum number of boxes is $\boxed{875}$.
