Answer : let A denote the event that a company executive will travel by plane and B denote the event of him travelling by train

Given : P(A) = 2/5, P(B) =1/3

To find : Probability of a company executive will be travelling by plane or train=P(A or B)

Formula used : P(A or B) = P(A) + P(B) – P(A and B)

Probability of a company executive will be travelling in both plane and train =P(A and B)= 0

(as he cannot be travelling by plane and train at the same time)

P(A or B) = 2/5  + 1/3   – 0

P(A or B) = 6+5/15 = 11/15

P(A or B)=11/15

Probability of a company executive will be travelling by plane or train= P(A or B) = 11/15