TANCET 2022 Solved Papers

Concept:Fill the four missing letters so that the block lengths of $a$'s and $b$'s increase in a regular pattern.Explanation:The given series is $\mathrm{aab\_aa\_bbb\_aaa\_bbb}$.Try option B: $\mathrm{baab}$.So the missing letters are $b$, $a$, $a$, $b$.After inserting them, the series becomes $\mathrm{aabb\,aaabbb\,aaaabbbb}$.Group the letters to see the pattern: $\mathrm{aa \mid bb \mid aaa \mid bbb \mid aaaa \mid bbbb}$.Thus, the series has $2$ $a$'s, then $2$ $b$'s, then $3$ $a$'s, then $3$ $b$'s, then $4$ $a$'s, then $4$ $b$'s.The number of letters in each block increases by one, which is a clear and consistent pattern.Therefore, option B correctly completes the series.Answer:B. $\mathrm{baab}$