Q. A person puts three cards addresses to three different people in three envelopes with three different addresses without looking. What is the probability that the cards go into their respective envelopes?
A) $\frac{2}{3}$
B) $\frac{1}{6}$
C) $\frac{1}{5}$
D) $\frac{2}{5}$
Explanation
(b)
Total number of ways placing 3 letters in three envelopes
$= 3! = 3 \times 2 \times 1 = 6$
Out of these ways only one way is correct
$\therefore$ The required probability $= \frac{1}{6}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.