Question

ulepulce
Problem Description - 6/15
1. A bullet train starts its journey from station A and reaches station B in 12 hours, which is at a distance of 720 km.
II. It reaches station C in the next 15 hours, which is at a distance of 1770 km from station A.
Which of the given statements are needed to find the average speed of the bullet train?
Correct answer: +1
Incorrect answer: 0
Options
I only
Il only
I and II both are sufficient
I and II are insufficient​

Answer 1

Correct option: I and II both are sufficient

Step-by-step explanation:

I.

Time taken, $t_{1}=12\:hours$

Distance covered, $d_{1}=720\:km$

Thus speed, $v_{1}=\frac{720}{12}\:km\:h^{-1}=60\:km\:h^{-1}$

II.

Time taken, $t_{2}=15\:hours$

Distance covered, $d_{2}=1770-720\:km=1050\:km$

Thus speed, $v_{2}=\frac{1050}{15}\:km\:h^{-1}=70\:km\:h^{-1}$

Conclusion:

We see that $v_{1}\neq v_{2}$ and thus we can conclude that to find the average speed of the bullet train, both the statements I and II are sufficient.