Step 1: Read the series.
The letters are A, G, L, P, S, and we need the next one.
Step 2: Find the gaps.
From A to G is a jump of 6 letters. From G to L is 5. From L to P is 4. From P to S is 3.
Step 3: See the pattern.
The jumps are getting smaller each time, 6, then 5, then 4, then 3.
Step 4: Next jump.
So the next jump should be 2.
Step 5: Apply it.
Move 2 letters ahead of S. After S comes T, then U. So the next letter is U.
Step 6: Conclusion.
The next term is U.
Answer: U