Answer:
3.333 hours
Explanation:
Given the total distance is 30 miles, and boat 1 travels at 3 mph and boat 2 travels at 6 mph, and the time for both is the same. Distance is speed S times time T so
30 = D(boat 1) + D(boat 2)
30 = (S1 * T) + (S2 * T)
30 = 3T + 6T
30 = 9T
3.333 = T