The correct option is: (C) 30
Explanation:
First arrange all of these numbers in ascending order:
57, 60, 69, 78, 89, 90, 95
The median (middle value) of the series is: 78
Now the left series to that median is: 57, 60, 69
The right series to that median is: 89, 90, 95
Now the median of the left series is: 60
The median of the right series is: 90
Take the difference of both to find the interquartile range: 90-60 = 30 (Option C)
