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2 years ago

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Two trains started moving at the same time, train A from Boston to New York, and train B from New York to Boston. The distance b

etween the train stations in New York and Boston is 240 miles. The average speed of train A is 60 mph, which is 3/4 of the average speed of train B.
How soon will the trains meet?

1 answer:

Ede4ka [16]2 years ago

7 0

Answer:

<u>After 1.7 hours</u>

Explanation:

<u>1. Calculate the average speed of train B</u>

60mph = 3/4 (s) ⇒ s = 60 (4/3) mph = 80 mph

<u>2. Build a table</u>

When the two trains meet:

Train Average speed Distance time (distance/average speed)

mph

A 60 x x/60

B 80 240 - x (240 - x) / 80

<u>3. Write the equation</u>

The time, when the two trains meet, is the same for both trains:

$\dfrac{x}{60}=\dfrac{240-x}{80}\\ \\ \\ 80x=14,400-60x\\ \\ 80x+60x=14,400\\ \\ 140x=14,400\\ \\ x=14,400/140\\ \\ x=102.85miles$

<u>4. Calculate the time:</u>

x/60 = 102.86 / 60 = 1.7 hours

The two trains will meet after 1.7 hours

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