Average (Railway Maths) (Part – II)

Total Questions: 50

31. The mean of the first ten even natural numbers is: [RRB NTPC 20/01/2021 (Evening)]

Correct Answer: (c) 11
Solution:

32. The mean of the first twelve prime number is: [RRB NTPC 20/01/2021 (Evening)]

Correct Answer: (a) 16.42
Solution:

33. The marks obtained in a test by students of a class are given below: 23, 2, 15, 38, 21, 19, 24, 26 Scores of how many students are within a +2 / −2 range of the average score of the class? [RRB NTPC 21/01/2021 (Evening)]

Correct Answer: (b) 3
Solution:

34. If each entry of a piece of data is increased by 7, then the arithmetic mean: [RRB NTPC 22/01/2021 (Morning)]

Correct Answer: (c) increases by 7
Solution:

35. If the arithmetic mean of 16, 18, 15, 17, p and 14 is 17, then the value of p is: [RRB NTPC 22/01/2021 (Morning)]

Correct Answer: (b) 22
Solution:

36. Sonam was given some money to take care of her travel during a 15-day sales drive she had to undertake. However, she had to increase her stay by another 9 days and as a result her average daily travel allowance went down by Rs 75. What was the amount that was sanctioned to her in the beginning? [RRB NTPC 31/01/2021 (Morning) ]

Correct Answer: (b) Rs 3,000
Solution:

37. 18 years is the average age of 36 boys and their professor. The average becomes 17 years if we leave the professor out. What is the age (in years) of the professor? [RRB NTPC 01/02/2021 (Morning)]

Correct Answer: (d) 54
Solution:

38. The average of 5 students in a class test is 39.20 and the average of three of them is 41. What is the average of the remaining two students? [RRB NTPC 01/02/2021 (Evening)]

Correct Answer: (c) 36.5
Solution:

39. In a class of 100 students, the mean marks obtained in a certain subject is 25 and in another class of 50 students, the mean marks obtained in the same subject is 70. The mean marks obtained by the students of both classes taken together is: [RRB NTPC 03/02/2021 (Morning)]

Correct Answer: (c) 40
Solution:

40. The average of four consecutive even integers is 27, what is the largest of these numbers ? [RRB NTPC 11/02/2021 (Evening) ]

Correct Answer: (c) 30
Solution: