Homework Help: Average speed help

1. Jan 13, 2010

jwang023

average speed help!!

1. The problem statement, all variables and given/known data

On your wedding day you leave for church 33.0 minutes before the ceremony is to begin, which should be plenty of time since the church is only 10.5 miles away. On the way, however, you have to make an unanticipated stop for construction work on the road. As a result, your average speed for the first 18.0 minutes is only 5.0 mi/hr. What average speed do you need for the rest of the trip to get you to church on time?

2. Relevant equations

average speed= distance/ time

3. The attempt at a solution

2. Jan 13, 2010

denverdoc

Re: average speed help!!

One approach is to to simply figure out how far you have traveled in the first 18 minutes.

Use your eqn. Then figure out how far you have left to go, and the time available to do it. This then will dictate the average speed required to arrive on time.

3. Jan 13, 2010

jwang023

Re: average speed help!!

Thanks for breaking it down!

4. Jan 13, 2010

denverdoc

Re: average speed help!!

No problem, welcome to PF.