Source: R & S (WWU students)

**Hint:** Draw a diagram....what formula expresses useful information relative to the problem?

**Solution Commentary:** Variation of soution commentary from R&S: Let d be the river's width, and r_{A} and r_{B} represent the rates of the two boats A and B. Then, meeting on the first trip across, t_{1} = 750/r_{A} =(d - 750)/r_{B}. Massaging this with some algebra, we get r_{A} = (750 r_{B})/(d - 750).

And meeting on the trip back, things are a little more complicated. We have t_{2} = (d - 750 + 250)/r_{A} =(750 + d - 250)/r_{B}. Massaging this with some algebra, we get r_{A} = [(d - 500)( r_{B})]/(d + 500).

Setting the two r_{A} equal, the r_{B} cancels and we get d = 2000.

Do you agree....What other solution approaches can you find?