(Mathematics) NDA/NA SOLVED PAPER 2023 – II (101 to 120)

Total Questions: 20

1. The sum of deviations of n numbers from 10 and 20 are p and q respectively. If (p - q)² = 10000 then what is the value of n?

Correct Answer: (a) 10
Solution:

2. Find value?

Correct Answer: (c) 112
Solution:

3. If the mean and the sum of squares of 10 observations are 40 and 16160 respectively, then what is the standard deviation?

Correct Answer: (d) 4
Solution:

4. Three dice are thrown. What is the probability of getting a sum which is a perfect square?

Correct Answer: (a) 17/108
Solution:

5. A, B. C and D are mutually exclusive and exhaustive events.

If 2P(A) = 3P(B) = 4P(C) = 5P(D) then what is 77P(A) equal to?

Correct Answer: (d) 30
Solution:

6. Two distinct natural numbers from 1 to 9 are picked at random. What is the probability that their product has 1 in its unit place?

Correct Answer: (d) 1/36
Solution:

7. Two dice are thrown. What is the probability that difference of number on them is 2 or 3?

Correct Answer: (b) 7/18
Solution:

8. Find value?

Correct Answer: (c) 5.5
Solution:

9. The probability that a person recovers from a disease is 0.8. What is the probability that exactly 2 persons out of 5 will recover from the disease?

Correct Answer: (d) 0.0512
Solution:

10. Suppose that there is a chance for a newly constructed building to collapse, whether the design is faulty or not. The chance that the design is faulty is 10%. The chance that the building collapses is 95% if the design is faulty, otherwise it is 45%. If it is seen that the building has collapsed, then what is the probability that it is due to faulty design?

Correct Answer: (b) 0.19
Solution: