If a boat is rowed downstream for 50 km in 5 hours and upstream for 24 km in 6 hours, what is the speed of the boat and the river?	Choose the most appropriate option.
A) (7 , 3) km/hr B) (7 , 9) km/hr C) (3 , 3) km/hr D) (7 , 5) km/hr E) (7 , 7) km/hr
Explanation:   If x: speed of boats man in still water   y: speed of the river   Downstream speed (Ds) = x + y   Upstream speed (Us) = x – y   x = (Ds + Us) / 2   y = (Ds – Us) / 2   In the above problem Ds = 10 ; Us = 4   x = (10 + 4) / 2 = 14/2= 
<gadget id="calculator">14/2</gadget>
<output>7</output>
7 km/hr   y= (10 - 4)/2 = 6/2= 
<gadget id="calculator">6/2</gadget>
<output>3</output>
3 km/hr   (7 , 3) km/hrNSWER: (7 , 3) km/hr
<result>A</result>
If a boat is rowed downstream for 50 km in 5 hours and upstream for 24 km in 6 hours, what is the speed of the boat and the river?