A pattern formed by two characters a and b is repeated more than once in the following string : × b × a × a × × a × a × bab What is × × in the 7th and 8th positions from the left in the above string?

The string is: × b × a × a × × a × a × bab. Looking at positions, the pattern 'ab' repeats: ×b ×a ×a ×× a×a× bab. If we identify the repeating pattern as '×a×b' or similar, the 7th and 8th characters need to fit. Counting position-by-position: pos1=×, pos2=b, pos3=×, pos4=a, pos5=×, pos6=a, pos7=×, pos8=×, pos9=a, pos10=×, pos11=a, pos12=×, pos13=b, pos14=a, pos15=b. The repeating block appears to be '×a×b' but to make the pattern consistent, positions 7 and 8 should be 'aa' so the full string reads ×b×a×a×aa×a×bab making the pattern (×a) repeating with bab terminating. The answer aa fits the repetition requirement.