Mathematics (NDA/NA SOLVED PAPER 2019 (I) (101 to 120)

Total Questions: 20

1. From a deck of cards, cards are taken out with replacement. What is the probability that the fourteenth card taken out is an ace?

Correct Answer: (d) 1/13
Solution:

Total number of possible outcomes = 52
And number of favourable outcomes = 4
∴ Required probability = 4/52 = 1/13

2. Simplify the equation?

Correct Answer: (d) 0.3
Solution:

3. A problem is given to three students A, B and C whose probabilities of solving the problem are 1/2, 3/4 and 1/4 respectively. What is the probability that the problem will be solved if they all solve the problem independently?

Correct Answer: (a) 29/32
Solution:

4. A pair of fair dice is rolled. What is the probability that the second dice lands on a higher value than does the first?

Correct Answer: (c) 5/12
Solution:

5. A fair coin is tossed and an unbiased dice is rolled together. What is the probability of getting a 2 or 4 or 6 along with head?

Correct Answer: (c) 1/4
Solution:

6. If A, B and C are three events, then what is the probability that atleast two of these events occur together?

Correct Answer: (c)
Solution:

7. If two variables X and Y are independent, then what is the correlation coefficient between them?

Correct Answer: (c) 0
Solution:

Correlation coefficient between two independent variables is zero.

8. Find the answer of given question?

Correct Answer: (b) 1/3
Solution:

9. The mean of 100 observations is 50 and the standard deviation is 10. If 5 is subtracted from each observation and then it is divided by 4, then what will be the new mean and the new standard deviation respectively?

Correct Answer: (c) 11.25, 2.5
Solution:

10. If two fair dice are rolled, then what is the conditional probability that the first dice lands on 6, given that the sum of numbers on the dice is 8?

Correct Answer: (c) 1/5
Solution: