Two customers Shyam and Ekta visit a shop on Tuesday to Saturday during a week. The visit not visit made by the each customer is at random. 

All possible outcomes are.

If Tuesday be (T) be Wednesday (W) and so Thursday (Th), Friday (F) and Saturday (S).

The all possible outcomes are :

(T, T), (T, W), (T, Th), (T, F), (T, S)

(W, T), (W, W), (W, Th), (W, F), (W, S)

(Th, T), (Th, W), (Th, Th), (Th, F), (Th, S)

(F, T), (F, W), (F, Th), (F, F), (F, S)

(S, T), (S, W), (S, Tb), (S, F), (S, S)

The total number of all possible outcomes = 25

(i) The favourable outcomes of the visit made by two customers on same day

= (T, T), (W, W), (Th, Th), (F, F), (S, S)

∴ The number of favourable outcomes = 5.

∴ The probability that the two customers visit the shop on same day 

= \(\frac { 5 }{ 25 }\) = \(\frac { 1 }{ 5 }\)

⇒ P(A) = \(\frac { 1 }{ 5 }\)

(ii) The favourable outcomes of visiting two customer on two consecutive days 

= (Shyam, Ekta) = (T, W), (W, Th), (Th, F), (F, S) 

or (Ekta, Shyam) = (W, T), (Th, W), (F, Th), (S, F)

∴ The number of favourable outcomes = 8

∴ The probability that two customers made the visit to the shop on consecutive days = \(\frac { 8 }{ 25 }\)

(iii) The probability ‘not visit’ made by two customers P(\(\overline { A }\)) = 1 – P(A) 

= 1 – \(\frac { 1 }{ 5 }\) = \(\frac { 4 }{ 5 }\)