1
NDA Mathematics 14 November 2021
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language
If $\rm \displaystyle \sum_{i = 1}^{10}x_i = 110$ and $\rm \displaystyle \sum_{i = 1}^{10}x_i^2 = 1540$  then what is the variance?
A
22
B
33
C
44
D
55
2
NDA Mathematics 14 November 2021
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language
3-digit numbers are formed using the digits 1, 3, 7 without repetition of digits. A number is randomly selected. What is the probability that the number is divisible by 3?
A
0
B
$\rm \frac{1}{3}$
C
$\rm \frac{1}{4}$
D
$\rm \frac{1}{8}$
3
NDA Mathematics 14 November 2021
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language
What is the probability that the roots of the equation x2 + x + n = 0 are real, where n ∈ ℕ and n < 4?
A
0
B
$\rm \frac{1}{4}$
C
$\rm \frac{1}{3}$
D
$\rm \frac{1}{2}$
4
NDA Mathematics 14 November 2021
MCQ (Single Correct Answer)
+2.5
-0.83
Change Language
If A and B are two events such that P(not A) = $\rm \frac{7}{10}$, P(not B) = $\rm \frac{3}{10}$ and P(A|B) = $\rm \frac{3}{14}$, then what is P(B|A) equal to?
A
$\rm \frac{11}{14}$
B
$\rm \frac{9}{14}$
C
$\rm \frac{1}{4}$
D
$\rm \frac{1}{2}$
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