Please answer both

1) The research and development department of a manufacturing company has identified 4 possible types of defects for a new product (A, B, C, D). The identified probabilities are 0.4, 0.3, 0.05, and 0.25, respectively. Of these defects, type D is the most serious and makes it impossible to use the product. The other defects have a solution. A pilot production program of 50 units will be launched and the mathematical expectation of defect D plus one standard deviation has been established as the maximum quality limit.

How much is this maximum quality limit?

a. 16 - b. 9.38 - c. 15 - d. 3.46 - e. 15.56

2) A company usually buys large batches of a certain kind of electronic device. Use a two-step method. First take a random sample of 50 samples. If you find 2 or less defective units, the lot is accepted. Otherwise, take a second random sample of 75 samples. If you do not find defective units, the lot is accepted. In case of finding one or more defective units, reject the lot. The probability of a defective part is historically known to be 2.333% and it remains constant.

What is the probability that the lot will be accepted?