Permutations and Combinations 1 Question 2
2. How many matrices with entries from are there, for which the sum of the diagonal entries of is 5 ?
(2017 Adv.)
(a) 198
(b) 162
(c) 126
(d) 135
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Answer:
Correct Answer: 2. (a)
Solution:
- Sum of diagonal entries of
is .
Possibilities
I.
II.
Total matrices