<span>Say the code only needed to be one number long. Going from 0-9, there are ten digits. Therefore, there are ten unique codes.
Now say the code has to be two numbers long. There are ten possibilities
for the first digit, 0-9. But the second digit only has nine
possibilities, since each number has to be different. (The first number
might be 0, so the second can only go from 1-9) For each of the first
ten possibilities, there are nine possibilities for the second. We
multiply those two numbers together, 10 * 9, and we get 90.
Now we just extend the logic. The third number only has eight
possibilities, while the fourth number only has seven. 10 * 9 * 8 * 7 =
5040 possible codes. I hope this helped! has a great day! :)</span>
An hourglass is turned over with the top part filled with
sand. after 3 minutes, there are 855 ml of sand in the top half. after 10
minutes, there are 750 ml of sand in the top half. This can be represents a two
points ( 3, 855) and (10, 750) . using this to solve the slope m =
(750-855)/(10-3) = -15. And using one point the equation is y = -15x + 900.
You would have to subtract both of them and you will get 9/10 stephens jump was further
