Murali travelled from city A to city B at a speed of 40 kmph and from city B to city C at 60 kmph. What is the average speed of Murali from A to C given that the ratio of distances between A to B and B to C is 1 : 3? Choose the correct choice from the following choices
A) 76.66 kmph
B) 69.66 kmph
C) 48 kmph
D) 66.66 kmph
E) 56.66 kmph
Let the distances between city A to B and B to C be 2x km and 3x km respectively.   Total time taken to cover from A to C   = (x)/40 + (3x)/60 = (3x + 6x)/120 = 9x/120 = 3x/40 Average speed = (2x + 3x)/(3x/40)   = 200/3 kmph.   =66.66 kmph   ANSWER:66.66 kmph
<result>D</result>
Murali travelled from city A to city B at a speed of 40 kmph and from city B to city C at 60 kmph. What is the average speed of Murali from A to C given that the ratio of distances between A to B and B to C is 1 : 3?