How do I solve Question 42, Level 5 in Think Different?

Solution 1:

If you have numbers X, Y, and Z, it looks like the trick is to

multiply the second digit of X by Y then append the result to the first digit of X to get Z.
50 + (3 * 3) = 59
90 + (2 * 4) = 98
30 + (2 * 4) = 38

If this is the case, the answer is

? = 9

Solution 2:

9.

Take the last digit of the numbers and divide the right number by the left one.

53 (3) 59 -> 3 9 -> 9 / 3 = 3  
92 (4) 98 -> 2 8 -> 8 / 2 = 4  
34 (2) 38 -> 4 8 -> 8 / 4 = 2  
71 (?) 79 -> 1 9 -> 9 / 1 = 9