1
NDA Mathematics 13 April 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language
If $A=\begin{bmatrix}1&2&2 \\ 2&1&2\\2&2&1\end{bmatrix}$ then what is equal to?
A
5I3
B
I3
C
I3
D
5I3
2
NDA Mathematics 13 April 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language
If the number of selections of r as well as things from 5n different things are equal, then what is the value of r?
A
n
B
2n
C
3n
D
4n
3
NDA Mathematics 13 April 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language
What is the number of selections of at most 3 things from 6 different things?
A
20
B
22
C
41
D
42
4
NDA Mathematics 13 April 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language

If $A=\begin{bmatrix}x&y&z\\y&z&x\\z&x&y\end{bmatrix}$

where x,y,z are integers, is an orthogonal matrix, then what is A2 equal to?

A
Null matrix 
B
Identity matrix
C
A
D
-A
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