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What average speed do you need to get you to the church on time?

ap physics question;
 
On your wedding day you leave for the church 34 minutes before the ceremony is to begin, which should be plenty of time since the church is only 12.0 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 17 minutes is only 5.0 mi/h. What average speed do you need for the rest of the trip to get you to the church on time?
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1 Answer

distance = rate*time
 
Note:  Since our time is in miles per hour,
to keep our units correct, we need to convert our
minutes into hours. 34 minutes is 34/60 of an hour,
and so forth.
 
How far do we go in 17 minutes at 5 mph?
d = 5(17/60) = 17/12 miles = 1 5/12 miles
 
How much distance is left?
12 - 1 5/12 = 10 7/12 miles
 
We now have 17 minutes left to travel 10 7/12 miles:
 
10 7/12 = r(17/60)
 
r = (127/12)(60/17) = 5(127)/17 = 37.353 mph