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Two trains starting from cities 300 miles apart head in oppo
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19 Oct 2017, 01:25
19 Oct 2017, 01:25
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Question Stats:
87% (00:59) correct
12% (01:34) wrong based on 24 sessions
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Two trains starting from cities 300 miles apart head in opposite directions at rates of 70 mph and 50 mph, respectively. How long does it take the trains to cross paths?
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2.5 hrs.
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Re: Two trains starting from cities 300 miles apart head in oppo
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19 Oct 2017, 01:40
19 Oct 2017, 01:40
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Bunuel wrote:
Two trains starting from cities 300 miles apart head in opposite directions at rates of 70 mph and 50 mph, respectively. How long does it take the trains to cross paths?
Enter your value
Kudos for correct solution.
Enter your value
Show: :: OA
2.5 hrs.
Kudos for correct solution.
When two trains are in opposite direction we add up the speed to get the relative speed i.e = 70 + 50 =120 mph
Now Time = \(\frac{Distance}{speed}\)= \(\frac{300}{120}\) = \(2.5 hours\)
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Re: Two trains starting from cities 300 miles apart head in oppo
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21 Aug 2020, 06:39
21 Aug 2020, 06:39
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Bunuel wrote:
Two trains starting from cities 300 miles apart head in opposite directions at rates of 70 mph and 50 mph, respectively. How long does it take the trains to cross paths?
Enter your value
Kudos for correct solution.
Enter your value
Show: :: OA
2.5 hrs.
Kudos for correct solution.
This is a shrinking gap question
70 mph + 50 mph = 120 mph
So, the gap shrinks at a rate of 120 mph
In order for the trains to cross the paths, the gap must shrink from 300 miles to 0 miles (at distance of 300 miles)
time = distance/ rate
= 300/120 hours
= 30/12 hours
= 5/2 hours
= 2.5 hours
Answer: 2.5
Cheers,
Brent
