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Bob travelled from City A to City B at an average speed of 30 kilometers/hour. For hisreturn trip he took a different route. The average speed of the return trip was 2/3 of the speed of the trip from City A to City B and the route he took from city A to City B is 1/5 longer than that of the return route. What is the average speed of total trip in kmph
(rounded to the nearest tenths place)?


A. 22.4
B. 24.4
C. 25.1
D. 26.4
E. 27.3

 Sep 27, 2020
 #1
avatar+27695 
+1

A-B    30 k/hr       1.2d / 30k/hr   = time

B-A    20 k/hr       d / 20k/hr = time

 

2.2d / (1.2d/30  +  d/20) =

2.2 / 1.2/30 + 1/20) = 24.4 k/hr

 Sep 27, 2020

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