Question

Two trains a and b leave delhi for bangalore at 9 am and 9:30 am respectively. Train a travels at a speed of 120 km/hr while train b travels at a speed of 150 km/hr. At what distance from delhi will the two trains meet?

Answer 1

Let trains meet after x km

time taken by train a for x km=(x/120)-1/2hr (since b started 1/2hr late from station)

time taken by train b for x km=x/150hr
$\frac{x}{120} - \frac{1}{2} = \frac{x}{150}$
5x-300=4x
x=300km

Answer 2

Answer:

Both train will meet after 300 km from Delhi.

Explanation:

Two trains A and B leave Delhi for Bangalore at 9 am and 9:30 am respectively.

Formula: d=rt

For train A:

Time: Let time t hours to reach Bangalore.

Speed = 120 km/h

Distance: Delhi to Bangalore is d

Distance covered by train A = 120t

For train B:

Time: Let time t-0.5 hours (because leave half hours later)

Speed = 150 km/h

Distance: Delhi to Bangalore is d

Distance covered by train B = 150(t-0.5)

Distance covered by train A is equal to train B when they meet because leave from same station.

Therefore,  120t = 150(t-0.5)

120t = 150t - 75

-30t=-75

t=2.5 hours

So, Both train will meet after 2 hours 30 minutes.

Now we find distance where they meet.

Distance covered by train A = 120t

                                               = 120 x 2.5

                                               = 300 km

Hence, Both train meet after 300 km from Delhi.