Outside a home, there is a 4-key keypad with letters Upper A comma Upper B comma Upper C comma and Upper D that can be used to

Question

2 years ago

13

open the garage if the correct four-letter code is entered. Each key may be used only once. How many codes are possible?

1 answer:

Nat2105 [25] · Answer 1 · 2022-03-06T09:29:52+03:00

Answer:

24 possible codes

Step-by-step explanation:

If every letter may be used only once, we can calculated how many codes are possible using the rule of multiplication as:

__4____ * ___3____ * ____2____ * ___1______ = 24

1st letter 2nd letter 3rd letter 4th letter

Because for the 1st letter of the code, we have 4 options, letter A, B, C and D.

Then for the 2nd letter, we only have 3 options because we can not choose the letter that we choose in the 1st letter.

So, the 3rd letter just have 2 options and finally, there is just one option for the 4th letter.

Outside a​ home, there is a 4​-key keypad with letters Upper A comma Upper B comma Upper C comma and Upper D that can be used to