7) A train starts from station A and reaches station D which is 150 km away. It has scheduled halts at station B and C for 5 minutes each. The distance between A and B is 50 km and C and D is 60 km. The train starts at 5 p.m. from A and reaches D at 8.30 p.m. What is its average speed in
Answers
Answer:
The thing you have to know here is that the ditance between A and D = 150km , A to B = 50 km and C to D = 60 km . The time by the train reached station A to D is 8:30p.m. Average speed -?
So here , he didnot give the distance from B to C ..
So first we need to find this ;
Total distance - [AtoB + Cto D]
= 150 - [ 50 +60]
= 150 - 110
= 40 km
So B to C = 40 km.
Now clearly we know that the train stopped at station B and C , thus after travelling 50km and again 40km ;
But time- ?
The train started at 5 p.m.
and reached at 8:30p.m.
Difference between 5p.m. to 8:30p.m.-?
= 8:30p.m.-5p.m.
= 3 1/2 hours.
Now exclude the extra [5x2 mins] for stopping at station to get accurate results.
3 1/2 hours - mins
= 60 x 3 + 30 mins
= 180 + 30 mins
= 210 mins - 5x2 mins
= 210 -10 mins
= 200 mins
= 200mins - hours
= 3.333hours
Average speed = distance / time
= 150km/3.333hours
= 45km/h
Therefore the average speed = 45km/h.