<PRE><B>Question 146824</B>
Let us assume the speed of the bus to be x as suggested in the question.

The equation for distance traveled is as follows :
           d = speed X time
So, the distance traveled by the bus can be written as :
           d = 12x

Now, the speed of the plane is said to be 120 + 5x which is 120km faster than 5 times the speed of the bus.  So the distance traveled by plane can be written as :
           d = 1.5 ( 120 X 5x)

We know that that the distance traveled by both the plane and bus is the same. So, we can equate the above two equations to give us :
           12x = 1.5( 120 X 5x)
           12x = 180 + 7.5x
           12x -7.5x = 180
           4.5x = 180
              x = 180/4.5
              x = 40

Ans. : The average speed of the bus is 40km/hour

The above question is solved by one of the experts from 24HoursTutor.com
We provide live 1:1 online homework help
1. 24X7 tutors available
2. Certified tutors
3. Only for $9.99/hr </PRE>