The probabilities that the serviceability of a new X-ray machine will be rated very difficult, difficult, aver-age,

Question:

The probabilities that the serviceability of a new X-ray machine will be rated very difficult, difficult, aver-age, easy, or very easy are, respectively, 0.12, 0.17, 0.34, 0.29, And 0.08. Find the probabilities that the serviceability of the machine will be rated
(a) Difficult or very difficult;
(b) Neither very difficult nor very easy;
(c) Average or worse;
(d) Average or better.