Q.

Let S={M=[aij],aij{0,1,2},1i,j2} be a sample space and A={MS:M is invertible} be an event. Then P(A) is equal to        [2023]

1 5081  
2 4781  
3 4981  
4 1627  

Ans.

(1)

Let M=[pqrs]    where p,q,r,s{0,1,2}

n(S)=34=81

First, we find p(A¯)

A¯={MS:|M|=0}

|M|=0ps=qr

ps=qr=0number of (p,q,r,s)=(32-22)2=25

ps=qr=1number of (p,q,r,s)=12=1

ps=qr=2number of (p,q,r,s)=22=4

ps=qr=4number of (p,q,r,s)=12=1

P(A¯)=3181P(A)=5081