it travels 19 miles in about 7 minutes. to the nearest mile per hour, what is this trains average speed in miles per hour?

Question

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Answer 1

To convert units without changing the value, we use the multiplicative identity (that is, 1).  We will need this information:

    60 minutes = 1 hour

 

So,

    19 miles in 7 minutes

    (19 miles)/(7 minutes)

    ( (19 miles)/(7 minutes) ) * 1

    ( (19 miles)/(7 minutes) ) * (60 minutes)(1 hour))

    (19/7) * (60)  miles/hour            [note: minutes cancel out]

    `163 mph     [rounded to the nearest mph]

 

p.s., Do you know the additive identity?

Answer 2

Convert the minutes into hours

 

number  Hours = (7/60) hrs

 

= 0.11666

 

Avg speed = Distance / Time

 

= 19 / ( 7/60)

 

= 162.86 mph