AMC 12 2006b Problem 5

John is walking east at a speed of 3 miles per hour, while Bob is also walking east, but at a speed of 5 miles per hour. If Bob is now 1 mile west of John, how many minutes will it take for Bob to catch up to John?

$\text {(A) } 30 \text {(B) } 50 \text {(C) } 60 \text {(D) } 90 \text {(E) } 120$