A lock has a code of 4 numbers from 1 to 10. If no numbers in the code are allowed to repeat, how many different codes could be made?
There are 10 options for the first number, 9 options for the second number (since one number has already been used), 8 options for the third number, and 7 options for the fourth number. Therefore, the total number of different codes is:
10 x 9 x 8 x 7 = 5,040
So there are 5,040 different codes that could be made if no numbers in the code are allowed to repeat.