Use Coupon: CART20 and get 20% off on all online Study Material

Total Price: Rs.

There are no items in this cart.
Continue Shopping
debadutta mishra Grade: 11

let A= set of 3x3 determinat having entries +1 or -1, if a determinat A1 is chosen randomly from the set of A,then the probability that the product of the elements of any row or any column of A1 is -1 is _

6 years ago

Answers : (2)

Jit Mitra
25 Points

I am not sure, but here is my best guess.



Sample Space = 2^9


(There are 9 positions, each position has two possiblities (-1 or +1) )


Favourable Outcomes :


Number of -1 in each row or coloumn should be odd.

So we get two cases here.

(i) No. of -1 in each row and coloumn is 3

(ii) No. of -1 in each row and coloumn is 1


Case 1:


This case can occur only when all the elements in the matrix is -1.


No. of favourable cases = 1


Case 2:


Consider the matrix row wise.

In the first row, you can put the -1 in any of the 3 places.

In the second row, you can put the -1 in two places (no below the previous one)

In the third row, you can put the -1 in only one place (remaining one, not below the other two).


So you get 3*2*1 = 6 possibilities in this case.


Total no. of favourable outcome = 6+1 = 7


So required probability is 7/29 ..

6 years ago
Jit Mitra
25 Points

Okay I missed a case.


All digits in a single row are -1. Rest of the elements are 1.

So we get 3 more cases.


So Probability = 10/2^9

6 years ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies
  • Complete JEE Main/Advanced Course and Test Series
  • OFFERED PRICE: Rs. 15,900
  • View Details

Ask Experts

Have any Question? Ask Experts

Post Question

Answer ‘n’ Earn
Attractive Gift
To Win!!! Click Here for details