Average Worksheet-1

Average Worksheet-1

1. David obtained 76, 65, 82, 67 and 85 marks (out of 100) in English, Mathematics, Physics, Chemistry and Biology. What are his average marks?

(a) 65                  (b) 69                 (c) 72                  (d) 76

(e) None of these

2. In Arun's opinion, his weight is greater than 65 kg but less than 72 kg. His brother does not agree with Arun and he thinks that Arun's weight is greater than 60 kg but less than 70 kg. His mother's view is that his weight cannot be greater than 68 kg. If all of them are correct in their estimation, what is the average of different probable weights of Arun ?

(a) 67 kg            (b) 68 kg            (c) 69 kg            (d) Data inadequate

(e) None of these

3. The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero?

(a) 0                    (b) 1                    (c) 10                  (d) 19

4. Find the average of all the numbers between 6 and 34 which are divisible by 5.

(a) 18                  (b) 20                 (c) 24                  (d) 30

5. The average of first five multiples of 3 is:

(a) 3                    (b) 9                    (c) 12                  (d) 15

6. The average of the first nine prime numbers is:

(a) 9                    (b) 11                   (c)                (d)

7. A student was asked to find the arithmetic mean of the numbers 3, 11, 7, 9, 15, 13, 8, 19, 17, 21, 14 and x. He found the mean to be 12. What should be the number in place of x ?

(a) 3                    (b) 7                    (c) 17                   (d) 31

8. The average of 2, 7, 6 and x is 5 and the average of 18, 1, 6, x and y is 10. What is the value of y?

(a) 5                    (b) 10                  (c) 20                  (d) 30

9. If the mean of 5 observations x, x + 2, x + 4, x + 6 and x + 8 is 11, then the mean of the last three observations is:

(a) 11                   (b) 13                  (c) 15                   (d) 17

10. If the mean of a, b, c is M and ab + bc + ca = 0, then the mean of a², b², c² is:

(a) M²                 (b) 3M²              (c) 6M²               (d) 9M²

11. The average of the two–digit numbers, which remain the same when the digits interchange their positions, is:

(a) 33                  (b) 44                 (c) 55                  (d) 66

12. The average of first 50 natural numbers is:

(a) 12.25            (b) 21.25            (c) 25                  (d) 25.5

13. The mean of 1², 2², 3², 4², 5², 6², 7² is:

(a) 10                  (b) 20                 (c) 30                  (d) 40

14. The average of all odd numbers upto 100 is:

(a) 49                  (b) 49.5              (c) 50                  (d) 51

15. If a, b, c, d, e are five consecutive odd numbers, their average is:

(a) 5 (a + 4)                                   (b)

(c) 5 (a + b + c + d + e)               (d) None of these

Answer Key:

(1)-e; (2)-e; (3)-d; (4)-b; (5)-c; (6)-c; (7)-b; (8)-c; (9)-b; (10)-b; (11)-c; (12)-d; (13)-b; (14)-c; (15)-d