Question

If the probability that A will live 15 years is 7/8 and that B will live 15 years is 9/10, then what is the probability that both will live after 15 years?

• A. $\frac{1}{20}$
• B. $\frac{63}{80}$
• C. $\frac{1}{5}$
• D. None of these

Answer 1

The correct option is B $\frac{63}{80}$

$P\left(A\right)\times P\left(B\right)=\frac{7}{8}\times \frac{9}{10}=\frac{63}{80}$