The distance between two stations X and Y is 520 km. A train starts from X at 9:00 a.m.
travels towards Y at 70 km/h. Another train starts from Y at 10:00 a.m. travels towards X at
80 km/h. At what time will the trains meet?
Answers
Given :-
▪ The distance between two stations X and Y is 520 km. train A starts from X at 9:00 am and travels towards Y at 70 km/hr .
▪ Another train B starts from Y at 10:00 am and travels towards X at 80 km/hr.
To Find :-
▪ Time at which the two trains will meet.
Solution :-
It is clear that the trains leave the station in a gap of 1 hour. Which means when the train B will leave the station X, train A will have travelled some distance. Let us find he distance,
⇒ Distance = Speed × Time
⇒ Distance = 70 × 1
⇒ Distance = 70 km
Now when the train B will leave the station X, train A would have travelled 70 km i.e., the two trains will be at a distance of 520 - 70 ⇒ 450 km
Since the trains are moving with respect to each other and in the opposite direction, so Relative velocity will be the sum of velocities.
⇒ Rel. velocity = 70 + 80
⇒ Relative velocity = 150 km/hr
So, The velocity of approach or simply relative velocity is 150 km/hr
Now, Let us find the time taken to travel the rest distance with relative velocity,
⇒ Distance = Speed × Time
⇒ 450 = 150 × Time
⇒ Time = 450/150
⇒ Time = 3 hours
But, This is the time after train B leaves, we need to find the time at which they will meet when train A leaves which is, 3 + 1 ⇒ 4 hours, Obviously.
Which means they would meet after 4 hours from 9:00 am
⇒ 1:00 pm
Hence, The time at which the trains will meet is 1:00 pm.
Answer:
ans will be 1:00 p. m
520-70 =450.
70+80=150
450/150=3
Time gap =1.
3+1=4.