After traveling 120 miles in 3 hours Rebecca reduced the speed of the sled by 10 miles per hour. How long did it take her to travel the next 450 miles?

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The answer isn't 5 hours.

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Answer 1 · 2018-03-26T01:31:32

It'd take her $15 h r s$ $15hrs$ to travel the next 450 miles.

Rebecca first travels $120 m i$ $120mi$ in $3 h r s$ $3hrs$ so

$\frac{120 m i}{3 h r s} = 40 m p h$ $(120mi)/(3hrs)=40mph$

Then she slows down by $10 m p h$ $10mph$ so

$40 m p h - 10 m p h = 30 m p h$ $40mph-10mph=30mph$

She has to travel $450 m i$ $450mi$ going at the speed of $30 m p h$ $30mph$ so

$\frac{450 m i}{30 m p h} = 15 h r s$ $(450mi)/(30mph)=15hrs$