Question

In a particular class, the probability of a student having blue eyes is 0.3, of having both blue eyes and blonde hair is 0.2, and of having neither blue eyes nor blonde hair is 0.5. What is the probability that a student in this class has blonde hair?

a) 0.5

b) 0.2

c) 0.3

d) 0.1

Answer 1

Let us denote the events

A : a randomly selected student have blue eyes

B : a randomly selected student have blonde hair

Given

That implies

using De-Moivre's Theorem

Now,

The probability that a student in this class has blonde hair