Each of the letters in the word CONTRAST is arranged in alphabetical order. How many letters are there in the English alphabetical series between the letter that is first from the left and the one that is fifth from the right in the new letter-cluster formed?

Correct — B.
Rule: sort the letters, find both positions, count the letters strictly between.

CONTRAST sorted: A C N O R S T T (both Ts kept).
First from the left: A(1).
Fifth from the right: T, T, S, R, O(15).

Letters between A and O are B to N: 15 − 1 − 1 = 13 → option (b).

Why the others are wrong

• (a)
  10 — 10 would need the second letter to be L(12), since 10 letters lie between A and L. Fifth from the right in A C N O R S T T is O, not L.
• (c)
  15 — 15 is O's own alphabet position. The question asks for the letters strictly between A and O, which are B to N, 13 of them.
• (d)
  11 — 11 is the count from C to O, D to N. C leads CONTRAST as written, but after sorting the cluster starts with A, which adds B and C.

Three moves solve this kind of item: sort the letters, locate the two positions, and count the alphabet letters strictly between them.

Keep repeated letters. CONTRAST has two Ts, and both sit at the right end of the sorted cluster, which is why fifth from the right is O. In an 8-letter cluster, fifth from the right is fourth from the left: 8 − 5 + 1 = 4.

Key facts

• CONTRAST sorted is A C N O R S T T.
• Fifth from the right of 8 letters is fourth from the left, since 8 − 5 + 1 = 4.
• The number of letters strictly between positions p and q is q − p − 1.

Common traps

• Dropping the second T: the cluster becomes A C N O R S T, fifth from the right becomes N, and the count becomes 12
• Answering with O's position, 15, instead of the letters between A and O

No directly related past PYQ was found.