Numbers 5, 15, 20, x, 28, 30, 35 are in ascending order and have median = 23; then the value of x is :

1. 24

2. 29

3. 17.5

4. 23

For numbers 10, 20, 30, 40, 50, 60, 70 and 80; the inter-quartile range is :

1. 20 + 60

2. 60 - 30

3. 60 - 20

4. 50 - 10

A student got the following marks in 9 questions of a question paper.
3, 5, 7, 3, 8, 0, 1, 4 and 6. Find the median of these marks.

The weights (in kg) of 10 students of a class are given below :

21, 28.5, 20.5, 24, 25.5, 22, 27.5, 28, 21 and 24. Find the median of their weights.