Question

The probability that a randomly chosen person is Rh-positive is 85%.

What is the probability that a randomly chosen person is Rh-negative?

What is the probability the next 5 people tested are Ph-positive?

What is the probability that out of the 5 people who have tested at least one is Rh-negative?

If two people get tested, what is the probability that one is Rh-positive and the other is Rh-Negative?

Answer 1

P(rh positive) = 0.85

1st part:

P(rh negative) = 1 - P(rh positive) = 1 - 0.85 = 0.15

2nd part :

P(5 people are all rh positive) = P(rh positive)^5

= 0.85^5

= 0.4437

3rd part :

P(atleast 1 is rh negative) = 1 - P(all are rh positive)

= 1 - 0.4437 {P(all are rh positive) from previous part}

= 0.5563

4th part :

P(1 rh positive , 1 rh negative)

= P(1st rh positive , 2nd rh negative) + P(1st rh negative , 2nd rh positive)

= P(rh positive)*P(rh negative) + P(rh negative)*P(rh positive)

= 0.85*0.15 + 0.15*0.85

= 0.255

(please UPVOTE)