Question

a 250 metre long train is moving at a constant speed of 72 km per hour how much time will it take to cross a bridge 150 metre long​

Answer 1

Answer:

0.00467

Step-by-step explanation:

[(250+150)/1000]\75

you add 250 with 150 because the train needs to completely cross the bridge and need to divide it with 1000 because you need to convert meter to kilometers.since time=distance/speed,you divide it with 75

Answer 2

It will take 20 seconds to cross the bridge.

Step-by-step explanation:

Speed of the train = 72 km per hour

∵ 1 km = 1000 meter

∴ 72 km = 72 × 1000 = 72,000 meter

1 hour = 3600 seconds

Speed of the train = $\frac{72000}{3600}$ = 20 meter/sec.

distance covered by train = length of the train + length of the bridge.

distance covered = 250 + 150

                             = 400 meter

Speed = $\frac{distance}{time}$

Let the time taken by the train  t sec.

$20=\frac{400}{t}$

20t = 400

t = $\frac{400}{20}$

t = 20

It will take 20 seconds to cross the bridge.

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