AFCAT Model Paper 6

Given:
A train covers 108 km in 3 hours with a constant speed V1.
The average speed of the train is 43.2 km/hour
And a certain distance with a constant speed V2 in next 2 hours
Formula used:
Speed = distance/time
Average speed = total distance covered /total time taken
Calculation:
Distance covered by the train with speed V1 = 108 km
Distance covered by the train with speed V2=V2×2=2V2
So, total distance covered =108+2V2
Total time = 3 + 2 = 5 hours
Now we can use,
Average speed = total distance /total time
⇒43.2=

(108+2V2)

5

⇒(108+2V2)=43.2×5
⇒(108+2V2)=216
⇒2V2=108
⇒V2=54
Now,
V1=

108

3

=36 km/hour
So, the required difference = V2–V1=54–36=18
∴ The difference between V2 and V1 is 18.