1/2of a certain travel is covered at the rate of 30km/hr, one-third at the rate of 40 km/hr and the rest at 35km/hr. Find the average speed for the whole travel. A) 33 1/3 B) 33 3/5 C) 34 3/7 D) None of these

1 Answer

Answer :

B)

let the total travel be X km. 

Then X/2 km at the speed of 30 km/hr and X/3 km at 40 km/hr and the rest distance( X - X/2 – X/3) =1/6 X at

the speed of 35km/hr.

Total time taken during the travel of X km

= X/2*30 hrs+ X/3*40hrs+

X/6*35hrs

= 5X/168 hrs

Average speed =X/(5x/168) = 168/5 =33 3/5km hr

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