Problema Solution
My cousin has 3 children. Both her and her husband are right-handed. Her first two children are left-handed and her youngest, a baby, is showing a preference for left-handedness.
If the probability of two right-handed parents having one left-handed child is 1/10, what is the probability of two right-handed parents having 3 left-handed children?
What is the probability of having at least one left-handed child?
Answer provided by our tutors
P(1 left-handed child) = 1/10
P(1 child is right-handed) = 1 - P(1 left-handed child) = 1 - 1/10 = 9/10
P(3 left-handed children) = (1/10)^3
P(3 left-handed children) = 0.001 or 0.1%
P(at least 1 left-handed child) = 1 - P(all 3 children are right handed)
P(at least 1 left-handed child) = 1 - P(1 child is right-handed)^3
P(at least 1 left-handed child) = 1 - (9/10)^3
P(at least 1 left-handed child) = 0.271 or 17.1%