Select the option that represents the letters that when sequentially placed from left to right in the blanks below will complete the letter series. Y _ Y _ _ Y _ T _ Y _ Y

Correct — D. Count the slots first, then find the repeating block.

The string Y _ Y _ _ Y _ T _ Y _ Y has twelve slots, and the blanks are slots 2, 4, 5, 7, 9 and 11.

Rule: the series repeats the three-letter group Y T Y end to end.

Slots 1-3: Y T Y — slots 4-6: Y T Y — slots 7-9: Y T Y — slots 10-12: Y T Y

The printed letters confirm it: Y at slots 1, 3, 6, 10 and 12, and the lone printed T at slot 8, which is the middle of the third group.

Reading the six blanks in order gives T, Y, T, Y, Y, T = TYTYYT — option (d).

Why the others are wrong

• (a)
  TYTYTY — This puts T at slot 9, right beside the printed T at slot 8. The group Y T Y never places two T's together.
• (b)
  YTYTYT — This puts Y at slot 2, so slots 1 to 3 read Y Y Y. The group needs a T in its middle position.
• (c)
  TTYYTT — This fills slots 4 and 5 as T then Y, so the second group reads T Y Y instead of Y T Y.

Blank-filling letter series are solved by finding the cycle length, not by guessing letters. Count the total number of slots, then look for a divisor that the printed letters support — twelve slots split cleanly into four blocks of three.

The printed letters are anchors. Any candidate block must reproduce every one of them in its correct slot, so a single misplaced anchor kills a block length immediately.

Once the block is fixed, filling the blanks is mechanical. The last step is the one most often fumbled: read the filled blanks left to right in slot order and match that string against the options.

Key facts

• Count the slots before guessing the block — twelve slots here, so a block of three fits four times.
• Use the printed letters as anchors that any proposed block must reproduce.
• The printed T at slot 8 sits in the middle of the third block, which fixes where the blocks start.
• The blanks are slots 2, 4, 5, 7, 9 and 11, and the answer must be read in that order.

Common traps

• Assuming a block length instead of counting the slots.
• Filling every blank correctly and then reading them out of slot order when matching an option.

No directly related past PYQ was found.