please go ahead and answer the last question which is (d) Please explain each step thoroughly

Exam 1 Page 6 a study of exercises, a large group of male runners walk on a treadmill for 6 minutes. Their heart rates in beats per minute at the end vary from runner to runner according to the Normal distribution with mean 104 beats per minute and standard deviation 12.5 beats per minute. (a) What percent of the runners have heart rates rates below 100 beats per minute? Let * be heart rate of runners Z X 6.88 Z 0. 1894 Or 18. 94 /0 (c) How high must the heart beat rate be to fall in the top 15% of all male runners? 85 0 B 2= 1.04 * = 104 + 1:04 ( 12.5 ) - 117 beats per minute d. Between what two values do the central 60% of all male Yumers