The current in a river is 3 mph. A boat can travel 21 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 choice from the following:  A) 69 miles  B) 88 miles  C) 96 miles  D) 102.8 miles  E) 112 miles
Upstream Speed = 21-3= 
<gadget id="calculator">21-3</gadget>
<output>18</output>
18mph   102.8 milesownstream Speed= 21+3= 
<gadget id="calculator">21+3</gadget>
<output>24</output>
24 mph   102.8 miles/18 + 102.8 miles/24= 10 hours   Solving for 102.8 miles we get 102.8 miles=102.8   Answer: 102.8 miles
<result>D</result>
The current in a river is 3 mph. A boat can travel 21 mph in still water. How far up the river can the boat travel if the round trip is to take 10 hours?