?
Two trains for Mumbai leave Delhi at 6 am and 6.45 am and travel at 100 kmph and 136 kmph respectively. How many kilometers from Delhi will the two trains be together:
Answer & Solution
Correct Answer:
Option
C
Difference in time of departure between two trains = 45 min. = $$\frac{{45}}{{60}}$$ hour = $$\frac{{3}}{{4}}$$ hour.
Let the distance be x km from Delhi where the two trains will be together.
Time taken to cover x km with speed 136 kmph be t hour and time taken to cover x km with speed 100 kmph (As the train take 45 mins. more) be
$$ {{\text{t}} + \frac{3}{4}} $$
= $$ {\frac{{4{\text{t}} + 3}}{4}} $$
Now,
100 × $$ {\frac{{4{\text{t}} + 3}}{4}} $$ = 136t
Or, 25(4t + 3) = 136t
Or, 100t + 75 = 136t
Or, 36t = 75
Or, t = $$\frac{{75}}{{36}}$$ = 2.083 hours
Then, distance x km = 136 × 2.083 ≈ 283.33 km.
Join the Discussion
Login to post a comment or share your explanation.
LoginB = train with speed 136kmph
And, Let x be the distance from Delhi to the point where the two trains meet.
Then,
time take by train A = x÷100 ( time = distance÷speed)
And,
time taken by train B = x ÷ 136
Difference in time taken = 45 minutes
Now
(x÷100)-(x÷136) = 45 minutes or 3/4 hr
Solve for x
Then you will get x= 283.33 km.
This is the answer
1st train go in this period=100*.75=75km
now relative speed =(136-100)=36km/hr
so 2nd train meet each other time is=75÷36=2.08
distance is=136*2.08=283.33km
Distance= (S1*S2*T) / (S1-S2)
where T= difference in time i.e. 45 min means 3/4 hrs. , S1 and S2 are speeds of given