1
NDA Mathematics 14 November 2021
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language
Let S = {2, 3, 4, 5, 6, 7, 9}. How many different 3-digit numbers (with all digits different) from S can be made which are less than 500?
A
30
B
49
C
90
D
147
2
NDA Mathematics 14 November 2021
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language
If p = (1111 ... up to n digits), then what is the value of 9p2 + p?
A
10n p
B
2p ⋅ 10n 
C
10np - 1
D
10np + 1
3
NDA Mathematics 14 November 2021
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language

The quadratic equation 3x2 - (k2 + 5k)x + 3k2 - 5k = 0 has real roots of equal magnitude and opposite sign. Which one of the following is correct?

A
0 < k < $\frac{5}{3}$
B
0 < k < $\frac{3}{5}$ only
C
$\frac{3}{5}$ < k < $\frac{5}{3}$
D
No such value of k exists
4
NDA Mathematics 14 November 2021
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language
If an = n(n!), then what is a1 + a2 + a3 +...+ a10 equal to?
A
10! - 1
B
11! + 1
C
10! + 1
D
11! - 1
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