Q. A five digit number is formed by writing the digits 1, 2, 3, 4, 5, in a random order without repetitions. Then the probability that the number is divisible by 4, is
A) 3/5
B) 18/5
C) 1/5
D) 6/5
Explanation
(c)
The number of divisible by 4, if last two digits are 12, 24, 32 and 52.
Remaining three place can be filled by 3! ways.
$\therefore$ Favourable cases $= 3! \times 4$
$\$Required probability $= \frac{3! \times 4}{5!}$
$= \frac{3! \times 4}{5 \times 4 \times 3!} = \frac{1}{5}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.