Distance, rate, and time problem. please help.

An editor left home at 7:15am and took a bus to the office. The bus averaged 27mph and arrived at the office building at 7:55am. At 5:00pm a coworker drove the editor home, where she arrived at 5:24pm. What was the average speed for the drive home?

Question

Distance, rate, and time problem. please help.

An editor left home at 7:15am and took a bus to the office. The bus averaged 27mph and arrived at the office building at 7:55am. At 5:00pm a coworker drove the editor home, where she arrived at 5:24pm. What was the average speed for the drive home?

whpalmer4 · Answer

well, to find the average speed, you need the time and the distance, right?  you have the time, but what about the distance?

anonymous · Answer

no distance.

whpalmer4 · Answer

right.  but do we have enough information to figure it out?  what's the point of all that stuff about the trip TO the office, hmm? :-)

anonymous · Answer

avg. 27mph?

whpalmer4 · Answer

okay, it averaged 27 mph.  how long did it take to get there, while traveling at 27 mph on average?  that should let us work out just how far it is.

anonymous · Answer

40 minutes

whpalmer4 · Answer

okay, how far do you go in 40 minutes @ 27 mph?

anonymous · Answer

d=rt right?

anonymous · Answer

18 miles? ;/

whpalmer4 · Answer

yes, that's correct!  

how fast do you have to go to cover 18 miles in the period between leaving the office and arriving home?

anonymous · Answer

r=d/t
r=18 miles/0.4
r=45 mph

anonymous · Answer

Thank you :)

whpalmer4 · Answer

that's the right answer!  good job!