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?

Mar 26, 2018

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

Explanation:

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

$\frac{120 m i}{3 h r s} = 40 m p h$

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

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

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

$\frac{450 m i}{30 m p h} = 15 h r s$