# A probability that any given person in a certain population is nearsighted is 0.15.

August 30, 2017

Question
6. A probability that any given person in a certain population is nearsighted is 0.15.
The probability that a person is color blind is 0.07. The probability that a person is
both nearsighted and color blind is 0.03.
a.) What is the probability that a person selected from this population is either
nearsighted or color blind (or both)?
b.) What is the probability that a person is suffering from neither of these two
visual impairments?
c.) What is the probability that a given person is nearsighted, but not color blind?
d.) What is the probability that a person is colorblind given that he or she is
nearsighted?
e.) What is the probability that a person is nearsighted given that he or she is color
blind?
7. At a certain boysâ€™ boarding school the following are all true statements:
30% of the boys are from the northeast.
25% of the boys are from the midwest
25% of the boys are from the south
20% of the boys are from the west
Of the northeastern boys, 20% are in the chess club and 40% are on the
debate team
Of the midwestern boys, 40% are in the chess club and 30% are on the
debate team
Of the southern boys, 30% are in the chess club and 60% are on the debate
team
Of the western boys, 50% are in the chess club and 10% are on the debate
team
a.) If a boy is chosen from the school at random, what is the chance he is in the
chess club?
b.) If a boy is chosen from the school at random, what is the chance he is on the
debate team?
c.) If a boy is chosen from the chess club at random, what is the chance he is from
the west?
d.) If a boy is chosen from the debate team at random, what is the chance he is
from the northeast?
8. A high school student is taking five courses and has homework in each of the
subjects every day. She insists on finishing the homework for one subject before
starting on the next.

a.) On any given day, in how many ways can she choose in what order she will do
the five homework assignments?
b.) On Tuesdays, she has study hall during the last period in the afternoon, and she
can finish any two of the homework assignments during study hall. In how many
ways can she choose which two assignments to do (regardless of what order she
does them)?
9. There are 15 jobs that need to get done and 25 people available to do them (and
capable of doing any of them). You must assign each job to just one person, and
you are not going to assign more than one job to any one person. In how many
ways can you assign the 15 jobs?
10. You must cancel your trip if any of three different problems come up. The
probability of the first problem coming up is 0.20. For the second and third
problems the probabilities are 0.25 and 0.10 respectively. Assume the probabilities
of the three problems are mutually independent. What is the probability you can