Question: Help with sequence and series problem ; plotting a series

Hey guys, I'm going to go ahead and post the whole problem along with some of the work that I've done so that it won't look like I'm letting somebody else complete the entire problem. Any help would be appreciated. Here goes:

Tom and Jerry are two snail brothers that need to travel five miles to a lake. Tom travels 1 mile on the first day, 1/2 on the second day, 1/3 on the third day and progresses 1/n miles each day. Jerry travels 2 miles on the first day, and on each successive day, he can only travel half the distance he traveled the previous day.

a) How far did Tom and Jerry travel by the end of the 10th day?

b) Plot the progress of Tom and Jerry on the same graph. 

c) How many days did it take for Tom to reach the lake

Okay, here are my answers, which I think are wrong.

a) 

a:=n->(1/n);
                            a := n -> 1/n

> 
> sum(a(n), n=1..10);

                                 7381
                                 ----
                                 2520

> evalf(%);

                             2.928968254 

Tom traveled 2.92878254

b:=n->(2^(2-n));
                                     (2 - n)
                          b := n -> 2

> sum(b(n), n=1..10);

                                32767
                                -----
                                8192

> evalf(%);

                             3.999877930

Jerry travelled 3.999877930

b) Here's where I have a problem with. How do you plot the progress of those two snails?