Probability Ques 42
Question-
An apartment has eight floors. An elevator starts with 4 passengers and drops at 8 floors of the apartment. What is the probability that all passengers ply to different floors?
(1) $\frac{95}{164}$
(2) $\frac{105}{256}$
(3) $\frac{110}{167}$
(4) $\frac{56}{123}$
(5) $\frac{10}{27}$
(IBPS RRBs Officer Scale-I CWE Main Exam, 13.10.2019)
Show Answer
Correct Answer: (2)
Solution: (2)
Total outcomes $=8^{4}=4096$
First person can select a floor in 8 ways, second person in 7 ways, third person in 6 ways and so on.
$\therefore$ Favourable outcomes $=8 \times 7 \times 6 \times 5=1680$
Required probability $=\frac{1680}{4096}=\frac{105}{256}$
BETA
