1
NDA Mathematics 13 April 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language
Consider the following for the two (02) items that follow:
The probabilities that A, B and C become managers are 3/10 1/2 and 4/5 respectively. The probabilities that bonus scheme will be introduced if A, B and C become managers are 4/9, 2/9 and 1/3 respectively.
If the bonus scheme has been introduced, then what is the probability that the manager appointed was B?
A
5/23
B
6/23
C
 7/23
D
8/23
2
NDA Mathematics 13 April 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language
The arithmetic mean of 100 observations is 50. If 5 is subtracted from each observation and then divided by 20, then what is the new arithmetic mean?
A
2.25
B
3.5
C
4.25
D
5.5
3
NDA Mathematics 13 April 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language
The standard deviation of 100 observations is 10. If 5 is added to each observation and then divided by 20, then what will be the new standard deviation?
A
0.25
B
0.5
C
0.75
D
1.00
4
NDA Mathematics 13 April 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language
If , and , then what is the value of ?
A
1/8
B
3/8
C
5/8
D
7/8
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