EXERCISE 6.A (OBJECTIVE TYPE QUESTIONS) (IN 1 5 SOLUTION)

Directions: mark against, the correct answer:

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)      76 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 and34 which are divisible by 5.

a)      18

b)      20

c)       24

d)      30

5.       The average first five  multiples of 3 is:

a)      3

b)      9

c)       12

d)      15

ANSWERS

1.E

2.E

3.D

4.B

5.B

SOLUTION

1.       Average = (76 + 65 + 82 +67 + 85/5) = (375 /5 ) = 75.

2.       Let Arun’s weight be X kg.

According to Arun, 5 < X < 2.

According to Arun’s brother, 60 < X < 70

According to Arun’s mother, x <68.

The values satisfying all the above conditions are 66 and 67.

 Required average = (66 + 67 /2) = (133 /2) =66.5 kg.

3.       Average of 20 numbers = 0.

Sum of 20 numbers = ( 0 x 20) =0.

It is quite possible that 19 of these numbers may be positive and if their sum is a, 

then 20^th number is (-a).

4.       Average = (10 + 15 + 20 + 25 + 30/5) = 100/5 = 20.

5.       Average = 3 (1 + 2 + 3 + 4 + 5) / 3 = 45 /5 = 9.