Q. Two numbers are selected randomly from the set $S = \{ 1,2,3,4,5,6\}$ without replacement one by one. The probability that minimum of the two number is less than 4, is
A) $\frac{1}{15}$
B) $\frac{14}{15}$
C) $\frac{1}{5}$
D) $\frac{4}{5}$
Explanation
(d)
Total ways $= 6 \times 5 = 30$
Favourable events = The minimum of the two numbers is less than 4.
$n(E) = 6 \times 4 = 24$
[We can select one from {1, 2, 3, 4} and other from (1 ,2, 3, 4, 5, 6)]
$\therefore$ Required probability $= \frac{24}{30} = \frac{4}{5}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.