Each of the letters in the word ‘MUSICAL’ is arranged in the English alphabetical order. How many letters are there in the English alphabetical series between the letter which is third from the left end and the one which is third from the right end in the new letter- cluster thus formed?

Correct — C. Sort the seven letters of MUSICAL: A C I L M S U.

Third from the left end = I.
Third from the right end = M (counting back U, S, M).

Between I(9) and M(13) lie J, K and L.
13 − 9 − 1 = 3 letters, which is option (c).

Why the others are wrong

• (a)
  Four — Four is the count with M included — J, K, L, M. The question asks for the letters lying between I and M, so neither endpoint is counted.
• (b)
  Two — Two is the gap between I and L. L is fourth from the right end of ACILMSU, not third; counting back gives U, S, M.
• (d)
  Five — Five counts both endpoints as well: I, J, K, L, M. Between means strictly between, so drop I and M and three remain.

Two small jobs sit inside one question. First rearrange the word alphabetically, then read a position off the new cluster.

The second job has a formula worth memorising. The number of letters strictly between positions p and q is q − p − 1.

Write the sorted cluster out once, number the letters from both ends, and the counting error that produces every wrong option here disappears.

Key facts

• MUSICAL in alphabetical order is A C I L M S U.
• I is the 9th letter of the alphabet and M the 13th.
• Letters strictly between two positions = higher − lower − 1, here 13 − 9 − 1 = 3.

Common traps

• Counting positions on MUSICAL itself instead of on the sorted cluster.
• Starting the count from the right at the wrong letter — U is first, S second, M third.
• Including one endpoint (giving 4) or both (giving 5).

No directly related past PYQ was found.