Problem Solving

Each employee at a certain bank is either a clerk or an agent or both. Of every three agents, one is also a clerk. Of every two clerks, one is also an agent. what is the probability that an employee randomly selected from the bank is both an agent and a clerk?
a)1/2
b)1/3
c)1/4
d)1/5
e)2/5

C

Source: Nova Math

Of every three agents, one is also a clerk. Let A, B and C are agents and one of them is clerk too, say B.

Of every two clerks, one is also an agent. Let B and D are clerks. Now we know that B is agent too, Now B and D are in accordance with the mentioned statement.

total outcome = 4 [A,B,C,D]
Favorable outcome = 1, i.e. B

1/4

Answer is C