I'm having a little trouble with this problem...

Please try and walk me through the problem, too:

#1. A motorboat leaves a dock and travels at an average speed of 15 mi/h toward an island. The average speed on the return trip is 10 mi/h. How far is the island from the harbor if the total trip takes five hours?

#2. A car traveling at 88 km/h overtakes a bus traveling at 64 km/h. If the bus has a 1.5 hour head start, how far from the starting point does the car overtake the bus?

Thank you so much! Any help is appreciated!