Question

$"A vehicle covers a distance of 40 km in first hour and a distance of 60 km in second hour of its motion. its average speed of motion is."$
One expert replied it '50 kmph' but a boy in my class assumed that because of 40 km in 1 hour, speed1 is '40 kmph' and because of 60 km in 1 hour, speed2 is 60 kmph and then he used a equation like "(2*Speed1*Speed2)/(Speed1+Speed2)" to get the answer as 48 kmph and my teacher said it as the correct one. Please explain how? 

The question above in italics is the same copied question from my teacher's quiz so please don't complain that I have written the wrong question.

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Answer 1

Answer:

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