Hello!
To find the interquartile you first have to find the median
20, 25, 30, 40, 40, 48, 50, 62
The median is 40
To find quartile 1 you find the median of the numbers less than 40
20, 25, 30
Quartile 1 - 25
To find quartile 3 you find the median of the numbers higher than 40
48, 50, 62
Quartile 3 - 50
The answers are
Quartile 1 - 25
Quartile 3 - 50
Hope this helps!