The speed of a 100 metre long train is 48 km/hour. That train can cross a bridge in 30 seconds. What is the length of the bridge?.
Answers
Step-by-step explanation:
The bridge is 300 meters long.
At 48 km/h the train goes 48000 meters in one hour. That means that it travels 48000 meters in 3600 seconds; which is equal to 13 and 1/3 meters per second. With that speed it takes 100 /13,333 seconds to go the whole length of the train; 100 meters. 100/13,333 is equal to 7,5 almost exactly. Then, divide 30 seconds with 7,5, and you get how many ‘train-lengths’ you travel in that sequence. 30 divided by 7,5 is exactly 4. Reduce 1 from 4 and you get 3. 3 train-lengths is the length of the bridge, which is equal to 300 meters.
Answer:
300 meters
Step-by-step explanation:
convert km/ hr into m/ sec by multiplying by 5/18
Speed= Distance/time
let's take bridge length as x,
Speed = 48* 5/18 = 40/3 m/sec
40/3 = ( 100+ x)/30
x= 300 meters