Question

A. 3/19 B. 4/19 C. 1/5 D. 5/19

Answer 1

$P(B|A)=\dfrac{P(A \cap B)}{P(A)}\\\\ |\Omega|=20\cdot19=380\\ |A|=5\cdot19=95\\ |A\cap B|=5\cdot4=20\\\\ P(A)=\dfrac{95}{380}=\dfrac{1}{4}\\ P(A \cap B)=\dfrac{20}{380}=\dfrac{1}{19}\\\\ P(B|A)=\dfrac{\dfrac{1}{19}}{\dfrac{1}{4}}=\dfrac{1}{19}\cdot4=\dfrac{4}{19}\Rightarrow B$