Testing between two means

A company, which has a large number of personal computers, is considering 2 training methods for its staff. Method A involves using a training manual. Method B involves taking a short training course. Before deciding on which procedure to adopt, the company selects 20 employees at random of whom 10 use the manual and 10 attend the short course. After a period in the work place, all 20 are given a problem to solve. The time taken in minutes to solve the problem is given below:

Training Method--------Time taken in minutes
A ---------------------29 36 42 30 31 43 46 27 38 17
B ---------------------44 34 37 38 46 50 44 40 42 43

(a) Test at 0.05 level of significance whether there is a difference between the two mean times.
(b) State the assumptions required to carry out the test in (a).
(c) Give also the p-value.