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17 votes
4. A train leaves Chicago for Milwaukee traveling at 14 meters/second. At the same time 100 miles away atrain leaves Milwaukee heading for Chicago traveling at 22 meters/second. How many seconds will havepassed when the two trains pass each other on parallel tracks?

User Northerner
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1 Answer

22 votes
22 votes

Train 1 from Chicago to Milwaukee = 14 meters/second

Train 2 from Milwaukee to Chicago = 22 meters/second

Distance between the two cities = 100 miles

Let's calculate the speed per hour of both trains, this way:

Train 1 = 14 meters/second * 60/60

Train 1 = 14 * 60 = 840 meters/minute

Train 1 = 840 meters/minute * 60/60

Train 1 = 50,400 meters/hour

Train 1 = 50.4 kilometers/hour

Train 1 = 50.4/1.609 per hour (to convert kilometers per hour to miles per hour)

Train 1 = 31.32 miles per hour

Now, let's calculate the speed per hour of the Train 2, as follows:

Train 2 = 22 meters/second * 60/60

Train 2 = 1,320 meters/minute

Train 2 = 1,320 meters/minute * 60/60

Train 2 = 79,200 meters/hour

Train 2 = 79.2 kilometers/hours

Train 2 = 79.2/1.609 per hour

Train 2 = 49.21 miles per hour

For finding the distance when the two trains will meet, we use the following equation:

Train 1 moving at 31.32 miles per hour, in t hours will cover 31.32t miles

Train 2 moving at 49.21 miles per hour, in t hours will cover 49.21t miles

31.32t + 49.21t = 100 (Distance between the two cities)

80.53t = 100

t = 100/80.53

t = 1.24 hours

t = 1.24 * 60 = 1 hour and 14 minutes, 24 seconds

Both trains will meet after 1 hour, 14 minutes and 24 seconds approximately

To convert this time to seconds, we do this:

1 hour to seconds = 60 * 60 = 3,600 seconds

14 minutes to seconds = 14 * 60 = 840 seconds

Total in seconds = 3,600 + 840 + 24

Total in seconds = 4,464

User Audrius
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