Question

The number of different signals that can be given using 4 different coloured flags without repetition is

• A. 32
• B. 24
• C. 64
• D. 72

Answer 1

Answer: (C)

64

Answer 2

By the formula in the synopsis,

$4P_{1} +^{4}P_{2} +^{4}P_{3} +^{4}P_{4} = 64$