Question

There are 12 persons seated in a line. Number of ways in which 3 persons can be selected such that atleast two of them are consecutive, is ______.

Options

• 100

• 200

• 300

• 400

Answer 1

There are 12 persons seated in a line. Number of ways in which 3 persons can be selected such that atleast two of them are consecutive, is 100.

Explanation:

Required ways = Total – (when no two of them are consecutive)

= ¹²C₃ – ¹⁰C₃

= 220 – 120

= 100