Jills bowling scores are approximately normally distributed with mean 170 and standard deviation 20, while Jacks scores

Question:

Jill’s bowling scores are approximately normally distributed with mean 170 and standard deviation 20, while Jack’s scores are approximately normally distributed with mean 160 and standard deviation 15. If Jack and Jill each bowl one game, then assuming that their scores are independent random variables, approximate the probability that
(a) Jack’s score is higher;
(b) The total of their scores is above 350.