Class - boys and girls

In the class are 60% boys and 40% girls. Long hair has 10% boys and 80% girls.

a) What is the probability that a randomly chosen person has long hair?
b) The selected person has long hair. What is the probability that it is a girl?

Correct answer:

p₁ =  0.38
p₂ =  0.8421

Step-by-step explanation:

$p_1=0.1\cdot 0.6+0.8\cdot 0.4=0.38$

$p_2=0.8\cdot 0.4\mathrm{/}{p}_1=0.8421$

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