Question

anyone who helps me gets a medal
A key code must contain 6 numerals. There are 10 numerals available. Using these numerals, how many different key codes may be created?
A. 151,200
B. 340
C. 210
D. 3,480

Answer 1

@waterineyes @LearningIsAwesome @loganmast @Abmon98

Answer 2

Suppose you have 6 blanks... Now you have to fill it with numerals and you are given with 10 numerals..

Answer 3

So, tell me the box which I have marked with 1 in figure, you can fill how many numerals there if you have 10 numerals??

Answer 4

for four of the will have two numerals and the others will have one

Answer 5

Wait.. Just look at box 1, I am giving you numerals from 0 to 9, You can put any one from 0 to 9 in that box?? Right??

Answer 6

right

Answer 7

You have 10 numerals means you have 10 digits, that are : 0,1,2,3,4,5,6,7,8,9

Answer 8

So, 1st box you can fill in how many ways???

Answer 9

ohh ok i get it now

Answer 10

You have any one to fill from 10 choices, you can fill 0, you can fill 1, you can fill 2 like wise in how many ways??

Answer 11

1st box you can fill in 10 ways as you have 10 choices. Suppose 1 box I have filled with 2..

Now moving to 2nd box..

You have used 2 in 1st box, now you have numerals with you as : 0,1,3,4,5,6,7,8,9 For 2nd box to fill you don't have 2..(I am assuming repetition of numerals is not allowed)..