Question:
The number of all possible matrices of order $3 \times 3$ with each entry 0 or 1 is
(a) 27
(b) 18
(c) 81
(d) 512
Solution:
(d) 512
There are 9 elements in a $3 \times 3$ matrix and one element can be filled in two ways, either with 0 or 1 .
Thus,
Total possible matrices $=2^{9}=512$