Analyzing the Series Pattern

The given series is: 2A, 3C, 5F, 7J, 11O, ?

We need to find the pattern governing both the numbers and the letters.

Number Sequence Logic

The numbers in the series are $2, 3, 5, 7, 11$.

• These numbers represent the sequence of prime numbers.
• The next prime number following $11$ is $13$.

Letter Sequence Logic

The letters in the series are A, C, F, J, O.

Consider their positions in the English alphabet:

• A = $1^{st}$
• C = $3^{rd}$
• F = $6^{th}$
• J = $10^{th}$
• O = $15^{th}$

Calculate the difference between consecutive positions:

• Position of C ($3$) - Position of A ($1$) = $2$
• Position of F ($6$) - Position of C ($3$) = $3$
• Position of J ($10$) - Position of F ($6$) = $4$
• Position of O ($15$) - Position of J ($10$) = $5$

The difference between the positions increases by $1$ each time ($+2, +3, +4, +5$).

The next difference in the sequence should be $6$.

Therefore, the position of the next letter is the position of O ($15$) plus $6$:

$15 + 6 = 21$

The $21^{st}$ letter of the alphabet is U.

Identifying the Next Term

Combining the next number ($13$) and the next letter ($U$), the missing term in the series is 13U.