The mean of x - 1, x + 1, x + 3 and x + 5 is

1. x + 1

2. x + 2

3. x + 3

4. x + 4

The mean of five numbers is 30. If one number is excluded, their mean becomes 28. The excluded number is

1. 28

2. 30

3. 35

4. 38

If each observation of the data is increased by 5, then their mean

1. remains the same

2. becomes 5 times the original mean

3. is decreased by 5

4. is increased by 5

The mean of 100 observations is 50. If one of the observation which was 50 is replaced by 150, the resulting mean will be

1. 50.5

2. 51

3. 51.5

4. 52