nhh4373
Answered

Discover a world of knowledge at Westonci.ca, where experts and enthusiasts come together to answer your questions. Connect with professionals ready to provide precise answers to your questions on our comprehensive Q&A platform. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.

a lock has a 4 digit combination where no number can be repeated how many possible combinations are there​

Sagot :

TheHarleyQuinn

Answer:

4,536

Step-by-step explanation:

Ok so lets write down any old 4 digit number

abcd

How many choices do we have for the digit a? We have 9 choices (since the first digit cannot be 0). Now for each possible choice of a we have 9 choices for b (since we want b to be a different digit to a and we now allow 0).

So for choice of the ab part we have 9∗9=81 possibilities.

Now for each of these we have 8 choices for c (to avoid c being the same as either a or b). And for each of these we have 7 choices for d (to avoid d being the same as either a,b or c).

So in total there are 9∗9∗8∗7=4536 possible numbers.

Thanks for using our service. We aim to provide the most accurate answers for all your queries. Visit us again for more insights. Thank you for visiting. Our goal is to provide the most accurate answers for all your informational needs. Come back soon. Westonci.ca is committed to providing accurate answers. Come back soon for more trustworthy information.