Q14 of 35 Page 55

A person travels along a straight road for the first t/3 time with a speed v1 and for next 2t/3 time with the speed v2 then the mean speed v is given by?

Given: Speed for first time = ..1

Speed for next time = ..2


To Find: Mean Speed


We know that mean speed is given by:


..3


Now, total time taken = ..4


Also, Distance = Speed × Time ..5


So, from 1 and 5 we get:


Distance for first time = ..6


And also distance for next time = ..7


So,


Total distance = (Adding 6&7) ..8


Now, by substituting 4 and 8 in equation 3, we get:



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