Question

A safe's lock has a three number combination. The

numbers on the safe lock are 0 - 9. How many
combinations are possible if no number may be used
more than once?

Answer 1

• 720 combinations

Explanation:

Each number has initially 10 options.

If one option used for the first number then the second number has one less, 9 options. Similarly, the third number has one less number of options than the second number, 8 options.

Total number of combinations is

• 10*9*8 = 720