Mathematics (NDA SOLVED PAPER 2020 – II) (101 to 120)

Total Questions: 20

1. The numbers 4 and 9 have frequencies x and (x − 1) respectively. If their arithmetic mean is 6, then what is the value of x?

Correct Answer: (b) 3
Solution:

2. If three dice are rolled under the condition that no two dice show the same face, then what is the probability that one of the faces is having the number 6?

Correct Answer: (c) 1/2
Solution:

3. Find the value?

Correct Answer: (c)
Solution:

4. The sum of deviations of n number of observations measured from 2.5 is 50. The sum of deviations of the same set of observations measured from 3.5 is − 50. What is the value of n?

Correct Answer: (d) 100
Solution:

5. A data set of n observations has mean 2M, while another data set of 2n observations has mean M. What is the mean of the combined data sets?

Correct Answer: (d) 4M/3
Solution:

6. The difference between number of students under Physics and Mathematics is largest for the interval

(Question:- 106-108) Read the following information and answer the three items that follow.

Correct Answer: (c) 40-50
Solution:

7. Consider the following statements:

1. Modal value of the marks in Physics lies in the interval 30-40.
2. Median of the marks in Physics is less than of marks in Mathematics. Which of the above statements is/are correct?

Correct Answer: (a) 1 Only
Solution:

8. What is the mean of marks in Physics?

Correct Answer: (c) 40.9
Solution:

9. What is the standard deviation of the observations √6, -√5, -√4, -1, 1, √4, √5, √6?

Correct Answer: (b) 2
Solution:

10. If Σxᵢ = 20, Σxᵢ² = 200 and n = 10 for an observed variable x, then what is the coefficient of variation?

Correct Answer: (d) 200
Solution: