Question

Alfredo has forgotten the five-digit code to the lock on his suitcase. Alfredo remembered that the first digit is 0 and the last digit is either 8 or 4. The middle digits could be any number from 0 through 9 inclusive. What is the greatest number of five-digit codes Alfredo might have to try in order to be sure to open his suitcase?

1,458
32
29
2,000

Answer 1

2 times (max # for a position)^3

Answer 2

go with the last one
you have 10 choices for the second third and 4th digit, 2 for the fifth
counting principle says to multiply all these together
\[10\times 10\times 10\times 2\]

Answer 3

So, what is the max # for a position? Look at position 2 and it goes from 0 to 10.

Answer 4

max # for position is 10?

Answer 5

Yes! Good work! so, 2 x 10^3

Answer 6

2000?

Answer 7

You got it, my friend!

Answer 8

thx :D

Answer 9

You're welcome. Satellite, thx for the recognition!