The sequence is: 2, 4, 8, 16, … Kabir thinks the next number is 18, because it looks like 2 was…

Why

Kabir checked only the first step (2 to 4, a jump of +2) and assumed the whole pattern follows that one rule — a completely reasonable first guess, but one extra check would have caught it. Look at the NEXT jump: 4 to 8 is +4, not +2 — if the rule were 'always add 2', the sequence would read 2, 4, 6, 8, 10, not 2, 4, 8, 16. What actually connects every step is that each number is DOUBLE the one before it: 2×2=4, 4×2=8, 8×2=16. Test it: checking every gap, not just the first one, is what separates a real pattern from a coincidence — 2→4 could fit either an 'add 2' or a 'double it' rule, but 4→8 only fits doubling. His sister is right: the next number is 16×2=32 — always check at least two consecutive gaps before deciding a pattern's rule, not just the first one.