Can someone tell me what is next in that 3 sequences?

I’m looking at three sequences from the test at http://free.ultimaiq.net/nse.htm. I managed to answer 27 of the 30 questions, but I’m really curious about the other three.

Q6: 1001, 4524, 4299, 3984, ? — here is something like
100 145 244 299 398 45+99+55+99 and the next one should be 398+65and+99 but its not

Q24: 50625, 1296, 8100, 3240, ? — I only know that the answer is not an integer and there is a hint “think how you can arrive at an+2 given an+1 and an”.

Q22: 38, 50, 22, 18, ?, ?