A man travels from A to B at a speed of 30 kmph and returns with a speed of 60 kmph. What is the average speed of the man?  Choose the correct choice from the following answers:  A) 47.5  B) 50  C) 45  D) 40  E) 30
Explanation:   The average speed ‘v’, when a man travels two same distance with different speeds ‘v1’ and ‘v2’ is:   v = (2*v1*v2) / (v1 + v2)   In the above problem, v1 = 30 and v2 = 60   Therefore, v = (2*30*60)/(30 + 60) = 3600/90= 
<gadget id="calculator">3600/90</gadget>
<output>40</output>
40   ANSWER 40
<result>D</result>
A man travels from A to B at a speed of 30 kmph and returns with a speed of 60 kmph. What is the average speed of the man?