A man can row 40 kmph in still water and the river is running at 10 kmph. If the man takes 1 hr to row to a place and back, how far is the place? Choose one
A) 16.5 kmph
B) 12.15 kmph
C) 2.25 kmph
D) 18.75 kmph
E) None of these
Explanation :   Let the distance be x   Speed upstream = (40 - 10)= 
<gadget id="calculator">(40 - 10)</gadget>
<output>30</output>
30 kmph   Speed downstream= (40 + 10)= 
<gadget id="calculator">(40 + 10)</gadget>
<output>50</output>
50 kmph   Total time taken= 1 hr   (x/50) + (x/30) = 1   ⇒8x/150 = 1   ⇒ x = 150/8= 
<gadget id="calculator">150/8</gadget>
<output>75/4 = around 18.75</output>
18.75 kmph. Answer : Option 18.75 kmph
<result>D</result>
A man can row 40 kmph in still water and the river is running at 10 kmph. If the man takes 1 hr to row to a place and back, how far is the place?