Q. The probability that a company executive will travel by train is $\frac{2}{3}$ and that he will travel by plane is $\frac{1}{5}$. The probability of his journey by train or plane is
A) $\frac{2}{15}$
B) $\frac{13}{15}$
C) $\frac{15}{13}$
D) $\frac{15}{2}$
Explanation
(b)
Let $E_{1}$ denote the event of travelling by train and $E_{2}$ denote the event travelling by plane.
$P\left( E_{1} \right) = \frac{2}{3},\ P\left( E_{2} \right) = \frac{1}{5}$
$P\left( E_{1} \cup E_{2} \right) = P\left( E_{1} \right) + P\left( E_{2} \right)$
$= \frac{2}{3} + \frac{1}{5} = \frac{13}{15}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.