Expected area of a field with measurement errors

A pitch is supposed to measure $300$ ft by $200$ ft. In practice the length is $300+X$ and the width is $200+Y$, where the errors $X\sim\text{Unif}(-15,15)$ and $Y\sim\text{Unif}(-5,15)$ are independent. What is the expected area of the pitch in square feet?

$61{,}500$. By independence, $\mathbb{E}[(300+X)(200+Y)]=(300+\mathbb{E}X)(200+\mathbb{E}Y)=300\times205=61{,}500$, since $\mathbb{E}X=0$ and $\mathbb{E}Y=5$.