Debbie is borrowing 3 books from her friend who has a collection of 45 books. which of the following expressions represents the number of ways debbie can choose a group of 3 books?
a.) p(45, 3)
b) c(45, 3)
c) 45!

As we observe clearly the problem given, it is clear that the order in which Debbie would choose the 3 books out of the total of 45 books is not important. This makes the problem an example of a Combination problem. The answer to this item is therefore letter B. C(45,3) read as combination of 45 taken 3. 

At a constant it will take one hour to travel 32 mi.at that speed it will take 1/2 hr to travel the remaining 16 mi.it will take 1+1/2 hr to travel the 48mi @ 32mph.so 1 hr = 60 min& 1/2 hr = 30 min1+1/2 hr = 90 min.there are 60s in each 90 × 60 = 3600 seconds.the real question seriously is he why are they driving so slow? ! lol.