need help in this probability and statistic question with steps, thank

A machine uses ball bearings from Companies E, F, and G in the ratio of 4:6:8. The lower and upper specication limits under which the ball bearings are suitable for the machine are 190mm and 216mm, respectively. Experience has indicated that the actual diameter of a randomly selected ball bearing from Company E is normally distributed, with a mean 198mm and a variance 36mm1. The actual diameter of a randomlyr selected ball hearing from Company F is normally distributed, with a mean 205mm and a variance 64mm2. The actual diameter of a randomly selected ball bearing from Company G is normally distributed, with the mean 210mm and the variance 1001111112. (a) There is 90% probability that the diameter of a randomly selected ball hearing from COmpany E is greater than d. Find a". The orders from Companies E, F, and G are combined and mixed thoroughly. (b) Find the probability that a ball bearing selected randomly from the combined order is suitable for the machine. (c) Given that a ball bearing selected randomly from the combined order is suitable for the machine, find the probability that it is from Company E