1.(iii) Two customers Shyam and Ekta are visiting a particular shop in the same week (Tuesday to Saturday). Each is equally likely to visit the shop on any day as on another day. What is the probability that both will visit the shop on (iii) different days?

Answers (1)
H Harsh Kankaria

Total possible ways Shyam and Ekta can visit the shop = 5\times5 = 25

(1) Case that both will visit the same day.

Shyam can go on any day between Tuesday to saturday in 5 ways.

For any day that Shyam goes, Ekta will go on a different day in (5-1) = 4 ways.

Total ways that they both go in the same day = 5\times4 = 20 

\therefore P(both\ go\ on\ different\ days) = \frac{20}{25} = \frac{4}{5}