1. J, L, N, P, ...
As we can see, this sequence is made of the alphabet. If we list the alphabet from J to P, we will have:
J, K, L, M, N, O, P
And the letters from the sequence are:
J, K, L, M, N, O, P
As we can see, the sequence is done by skipping the next letter of the alphabet. Listing it further will let us know the next three letters of the sequence.
J, K, L, M, N, O, P, Q, R, S, T, U, V, ...
Therefore, for number 1, the next three letters would be R, T, and V.
2. t, s, r, q, ...
The next one still consists of the alphabet. This sequence listed the alphabet in reverse order from the letter t. Knowing this, we can say that the next letters in the sequence are p, o, and n.
3. ↓←↑→↓
This sequence is quite simple. If we follow the direction of the arrows, we can see that it goes on a loop:
With this, we can say that the next three patterns for the sequence will be ←↑→
4. 4a, 5b, 6c, …
For this sequence, we can see that as the alphabet goes on from a to c, the numbers also go on from 4 to 6. With this, we say that the next letters would be d, e, and f, while the next numbers would be 7, 8, and 9. The next three elements of the sequence would be 7d, 8e, and 9f.
5. x, 2x, 3x, …
For this, we can see that as the sequence goes on, the 'x' remains, and the number goes from 1, 2, and 3. Continuing, we will have 4, 5, and 6. Therefore, the next elements would be 4x, 5x, and 6x