Question

An automobile travels on a straight road for 55 km at 20 km/h. It then continues in the same direction for another 60 km at 55 km/h. What is the average velocity (km/h) of the car during the full 115 km trip

Answer 1

Given :

Speed of automobile for first 55 km ,
`v_1=20\ km/h` .

Speed of automobile for first 60 km ,
`v_2=55\ km/h` .

To Find :

Average velocity of the full trip .

Solution :

We know , average velocity is given by :

`v_(avg)=\frac{\text{Total distance covered}}{\text{Total time taken }}`

Now , time is given by :

`T=(D)/(v)`

So ,

`v_(avg)=(55+60)/((55)/(20)+(60)/(55))\\\\v_(avg)=29.94\ km/h`

Therefore , the average velocity (km/h) of the car during the full 115 km trip is 29.94 km/h .

Hence , this is the required solution .