When displayed on a seven-segment display, which number is next in this sequence?
8, 7, 3, 5, ?
Each number is the number of segments used to display the previous number. So 8 requires 7 segments, 7 needs 3 segments, 3 uses 5 segments, and 5 requires 5 segments.
Thus, the next number (and all subsequent numbers) is 5.