Question

probability question no . 27 please

Answer 1

27.

Given that two friends visit a particular shop in the same week from Tuesday to Saturday.

Total number of days = 5(Tues, Wed, Thurs, Fri, Sat).

Both of them can visit the shop in 5 * 5 = 25 ways.

Hence Total number of events n(S) = 25.


(1) On the same day:

Let A be the event of visiting a shop on the same day.

n(A) = {T,T},{Wed,Wed},{Thurs, Thurs},{Fri, Fri}, {Sat, Sat}

        = 5.

Hence required probability P(A ) = n(A)/n(S)

                                                      = 5/25

                                                      = 1/5.



(2) On consecutive days:

Let B be the event of visiting the shop on consecutive days.

n(B) = {Tu,Wed},{Wed,Tu},{Wed,Thu},{Thu,Wed},{Thu,Fri},{Fri,Thu},{Sat,Fri},{Fri,Sat}

        = 8

Hence required probability P(B) = n(B)/n(S)

                                                      = 8/25.



(3) On different days:

Let C be the event of visiting the shop on different days.

P(C) = 1 - Probability of visiting the shop on the same day.

        = 1 - 1/5

       = 4/5.



Hope this helps!