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Texas Instruments technical mcq question, verified with a worked answer. Free to practise - no sign-up.
Bella arranging books**
Bella is arranging her books on a new bookshelf. She has placed B1 in the 24th position from the left and B2 in the 27th position from the right.
What is the minimum number of books that Bella owns if only B3 is exactly in between B1 and B2?
Note: Bella is placing all her books on the bookshelf.
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Show answer & explanation
For minimum books, the positions overlap with B2 to the left of B1. With B3 between them, B2 is at 24 - 2 = 22 from left. Given B2 is 27th from right, total books = 22 + 27 - 1 = 48.
Step-by-step Derivation:
Step 1: For minimum books, arrange books with maximum overlap: B2 is placed to the left of B1.
Step 2: Since only B3 is between B1 and B2, B1 is 2 positions to the right of B2 (or B2 is at position 24 - 2 = 22 from the left).
Step 3: B2 is also 27th from the right.
Step 4: Total books N = Position_left + Position_right - 1 = 22 + 27 - 1 = 48.