Probability Question 125
Question: Let A and B be two finite sets having m and n elements respectively such that $ m\le n. $ A mapping is selected at random from the set of all mappings from A to B. The probability that the mapping selected is an injection is
Options:
A) $ \frac{n!}{(n-m)!m^{n}} $
B) $ \frac{n!}{(n-m)!n^{m}} $
C) $ \frac{m!}{(n-m)!n^{m}} $
D) $ \frac{m!}{(n-m)!m^{n}} $
Show Answer
Answer:
Correct Answer: B
Solution:
As we know the total number of mappings is $ n^{m} $ and number of injective mappings is $ \frac{n!}{(n-m)!n^{m}} $ .