A train is crossing two bridges of 430m and 550m in 30sec and 36 sec respectively. find the speed of the train ?
2006-09-04 05:22:33 · 8 answers · asked by madan raj 1 in Science & Mathematics ➔ Mathematics
Assumptions:
The distance between the 2 bridges are negligible.
Total distance travelled = (430 + 550) m = 980 m
Total time taken = (30 + 36) sec = 66 sec
We will calculate the Average Speed of the train as
Average Speed = Total distance travelled / Total time taken
= 980 / 66 m/sec
= 14.8 m/sec (answer)
2006-09-04 05:30:51 · answer #1 · answered by tjoyce71 1 · 0⤊ 0⤋
When train is crossing the bridge we have to take the length of the train also
Let the length of the train is x meter then
Total distance travel led for crossing 1st bridge= {430+x}...........i
Total distance travel led for crossing 2 ND bridge= {550+x}.........ii
Since the speed in both of the cases is same, therefore
{430+x}/30 = {550+x}/36
{430+x}/5 = {550+x}/6
By cross multiplication
6 {430+x} = 5{550+x}
2580 +6x = 2750 +5x
6x -5x = 2750 -2580
x = 170 meter
Therefore the length of the train is 170 meter
Hence speed = {430+170}/30=600/30 =20meter/second
or you can solve
difference in lengths of two bridges=550-430=120meters
difference in time for crossing bridge = 36-30 =6 second
Therefore Speed of train = 120/6 = 20 meters/second
2006-09-04 06:01:08 · answer #2 · answered by Amar Soni 7 · 0⤊ 0⤋
430+550=980 meters (in 66 sec)
66 secs is 1.1 min divide 60 (1 hour) by 1.1 (min)=54.54
this is the relationship number between the distance and 1 hour
multiply 0.98 (kilometers) by 54.54 = 53.45kph
or 980 meters is to 66 secs as X is to 3600 sec
980/66=x/3600
980*3600=66x
3528000=66x
x=53.45kph
2006-09-04 06:05:43 · answer #3 · answered by Ford Prefect 7 · 0⤊ 0⤋
The formula for rate is:
r = d/t
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The total distance
430m + 550 m = 980 m
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Total time:
30 sec + 36 sec = 66 seconds
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solving for rate
980 ÷ 66 =14.84848485 meters per second
rate = 14.8 m/s rounded to one decimal place
The answer is:
rate= 14.8 m/s
2006-09-04 06:50:10 · answer #4 · answered by SAMUEL D 7 · 0⤊ 0⤋
It takes 6 seconds to travel 120 metres, so the speed is 20 Metres per second.
2006-09-04 05:25:57 · answer #5 · answered by JeffE 6 · 0⤊ 0⤋
Average speed = difference of space/difference of time
v=(550-450)m/(36/30)s
v=120m/6s=20m/s
JeffE is right.
2006-09-04 05:48:05 · answer #6 · answered by Francesco 2 · 0⤊ 0⤋
average speed =totaldistance travelled/total time taken
=(430+550)m/(30+36)sec =980m/66sec =>14.85 m/s
2006-09-04 05:33:12 · answer #7 · answered by raj 7 · 0⤊ 0⤋
340km/hour
2006-09-04 05:30:33 · answer #8 · answered by Anonymous · 0⤊ 0⤋