[bonanova]

Here are three number strings:
5 8 2 7 4 9
9 4 7 8 5
5 8 7 9
which string comes next?
7 8 5
8 7 9
9 8 5
9 7 8

[Guest]

Here are three number strings:
5 8 2 7 4 9
9 4 7 8 5
5 8 7 9
which string comes next?
7 8 5
8 7 9
9 8 5
9 7 8

9 8 5
The left hand digit alternates 9 and 5, and so does the right

[Guest]

4. 9 7 8

It looks like the string is being reversed each time, and the 4th digit removed. So reversing it would give you 9 7 8 5 and then remove the 5.

[bonanova]

Bingo.

I removed the lowest digit each time, but that turns out to the the 4^th digit after reversal.

[Guest]

9 7 8

Everytime the string is inverted and 4th last digit is omitted

[Guest]

Here are three number strings:
5 8 2 7 4 9
9 4 7 8 5
5 8 7 9
which string comes next?
7 8 5
8 7 9
9 8 5
9 7 8


Can I have a different answer?

Every time you revert the numbers, you remove the digit, is so happen to be the number which is 2^(n-1), where n is the row number.
Line 2, you removed 2 ( 2^1 = 2)
line 3, you removed 4 (2^2 = 4)
so I though line 4 should remove 8 (2^3 = 8)
then my answer become 975, which is not in the list of choices.

sorry, not try to be different, just point out the coincidence I found.

[Guest]

thats easy.

4. unless you want to get more complicated and find a different answer.