Answer:
24
Explanation:
For ABCD the three longest are:
60,40,30
60 to 40 is 20
40 to 30 is 10
so each time it's decreasing by 1/2
For EFGH the two shortest are:
6 and 12
12 to 6 is 1/2
Assuming there is a pattern
it logically would be 24
as 12(2)=24