The current in a river is 5 mph. A boat can travel 20 mph in still water. How far up the river can the boat travel if the round trip is to take 10 hours?  Choose the correct option:
A) 69 miles
B) 88 miles
C) 93,75 miles
D) 100 miles
E) 112 miles
Upstream Speed = 20-5= 
<gadget id="calculator">20-5</gadget>
<output>15</output>
15 mph   Downstream Speed= 20+5= 
<gadget id="calculator">20+5</gadget>
<output>25</output>
25 mph   D/15 + D/25= 10 hours   Solving for D we get D=93,75   Answer: 93,75 miles
<result>C</result>
The current in a river is 5 mph. A boat can travel 20 mph in still water. How far up the river can the boat travel if the round trip is to take 10 hours?