1. The instructor in a Humanities class says that students have a 15% probability of making an A in her class, 20% probabilty of making a B, 25% chance of making a C, and 20% chance of making a D. The possible grades that can be assigned are A, B, C, D, and F. Assume one student is chosen at random. What is the probability that this student failed, that is earned a D or F grade?
a. 20%
b. 4%
c 40%
d can not be determined from the information given
2. A human gene carries a certain disease from a mother to her child with a probability rate of 0.58. That is, there is a 58% chance that the child becomes infected with the disease. Suppose a female carrier of the gene has five children. Assume that the infections, or lack thereof, are independent of one another. Find the probability that all five of the children get the disease from their mother.
A) 0.934
B) 0.066
C) 0.013
D) 0.018