A rower can row upstream at 7 km/hr and downstream at 11 km/hr. What is the rower's rate in still water?
Choose the correct choice from the following options.
A) 7.5 km/hr  B) 8.0 km/hr  C) 8.5 km/hr  D) 9.0 km/hr  E) 9.5 km/hr
The rate in still water is 1/2 * (11 + 7)= 
<gadget id="calculator">1/2 * (11 + 7)</gadget>
<output>9</output>
9 km/hr   The answer is 9.0 km/hr.
<result>D</result>
A rower can row upstream at 7 km/hr and downstream at 11 km/hr. What is the rower's rate in still water?