In the sequence of the terms AD CG FK JP, the next term is

Observe the first letters: A, C, F, J; the difference between each consecutive letter is incrementing by one letter. Or if we number the letters, the sequence is 1, 3, 6, 10 and the difference of the consecutive numbers in order is 2, 3, 4. Hence, the next difference is 5 and so the next number is 10 + 5 = 15, i.e. letter ‘O’. Observe the second letters: D, G, K, P; if we number these letters, they are 4, 7, 11, 16 and the difference of the consecutive numbers in order is 3, 4, 5. Hence, the next difference is 6 and so the next number is 16 + 6 = 22, i.e. letter ‘V’. Hence, the next term is ‘OV’.