Series Sequence in Aptitude : Practice MCQ Questions & Answers with Explanations

The series consists of squares of natural numbers ($2^2, 3^2, 4^2$, etc.). The number 27 is a cube ($3^3$), making it the odd one out in this sequence.

In all other numbers, the sum of the first and third digits equals the middle digit (e.g., 1 + 3 = 4 for 143). For 353, 3 + 3 = 6 (not 5), making 353 the odd one out.

This is a geometric progression with a common ratio of 3. The 8th term is found using $a \times r^{n-1} = 2 \times 3^7 = 2 \times 2187 = 4374$.

The given series consists of perfect cubes ($1^3, 2^3, 3^3$, etc.). Among the options, 256 ($16^2$ or $4^4$) is not a perfect cube, making it the odd one out.

The correct pattern follows $n \times 1 + 1$, $n \times 2 + 2$, $n \times 3 + 3$, etc. Therefore, the term after 10 should be $10 \times 3 + 3 = 33$, but the series has 32, making it the odd one out.