What comes next in the series: A, D, G, J?

To determine what comes next in the series A, D, G, J, it is essential to identify the pattern of the sequence. The letters can be translated into their corresponding positions in the alphabet: A is 1, D is 4, G is 7, and J is 10.

When examining the differences between these consecutive positions, we find that each letter's position increases by 3:

• From A (1) to D (4), the increase is 3.

• From D (4) to G (7), the increase is again 3.

• From G (7) to J (10), the increase is still 3.

Following this established pattern, the next letter would be determined by adding another 3 to the position of J (10). Thus, 10 + 3 equals 13, which corresponds to the letter M in the alphabet.

Hence, the next letter in this series will be M.