Question

How many 5 digit codes can be formed from the digits 1,2,3,4,5,6 and 7 if digits cannot be repeated

Answer 1

- You pick the first digit at random - you have 7 possible outcome. For the next digit, as you cannot have repetitions, you only have 6 possible outcomes. And for the second one 5, the third one 4 and the fourth one 3, and lastly the third one, which is 2.

- So you have 7×6×5×4×3×2 possible outcomes.

= 17640