Question

Given 4 flags of different colours , how many different signals can be generated, if a signal requires the use of 2 flags one below the other?[By default, repetition is not allowed unless it is said in the question.]

• A. 6
• B. 8
• C. 10
• D. 12

Answer 1

The correct option is D

12

Given that the signal requires 2 flags one below the other.

Let us visualize the signal as

We have 4 different flags. The upper part of the signal can be picked from the 4 different flags. The lower part of the signal can be picked from the 3 remaining different colours. So, by the fundamental principle of counting, total no.of ways a signal can be made = 4 $\times$ 3 = 12