Question

a train leaves station a at 5 a.m and reaches station b at 9am on the same day.another train leaves station b at 7 a.m and reaches station a at 10:30am on the same day.the time at which the two trains cross each other is?

Answer 1

Answer:

Step-by-step explanation:

M takes 4 hrs to go from A to B

and

N takes 3.5 hrs to from B to A

also

Train N leaves B, 2 hrs after M leaves A

:

It will easier if we choose a distance value for A to B

I chose 280 mi, both 4 and 3.5 will divide into it evenly

Find the speed of both trains from this

280/4 = 70 mph speed of M

280/3.5 = 80 mph speed of N

:

When they cross the total distance traveled by both trains = 280 mi

Let t = time (hrs) of train M

then

 

(t-2) = time of train N

:

Dist = speed * time

70t + 80(t-2) = 280

70t + 180t - 160 = 280

150t = 280 + 160

t = 440%2F150

t = 2140%2F150 = 214%2F15 hrs travel time of M when the cross

:

Change 14/15 hrs to min: 14/15 * 60 = 56 min

:

2 hr 56 min from 5 am = 7:56 am time when they cross.

:

:

Check solution (train N travel time will be 56 min or 14/15 hr

N dist: 14/15 * 80 = 74.67 mi

M dist: 44/15 * 70 =205.33 mi

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Train dist totals: =280 mi