Answer:
 38
Step-by-step explanation:
Sequential pairs will be ...
 38 - 87
 79 - 96
 17 - 74 or 79
 43 - 38
 74 - 43
 96 - (none)
 87 - 74 or 79
We notice that 17 has no preceding number. It must be first in the list. 79 cannot be second, because that skips a bunch of numbers. The sequence appears to be ...
 17 - 74 - 43 - 38 - 87 - 79 - 96
The 4th number in the list is 38.
