A 5-digit combination lock can be opened only if a correct combination of digits is chosen. Find the probability of guessing the

Question

3 years ago

10

A 5-digit combination lock can be opened only if a correct combination of digits is chosen. Find the probability of guessing the

correct combination if:
A. no digit is repeated
B. digits can repeat and zero is not one of the digits in the combination

Mathematics

1 answer:

Anarel [89] · Answer 1 · 2022-08-11T20:35:05+03:00

1) If digits can not repeat, the number of possible variations is 10x9x8x7x6 =30,240

And the probaility of guessing is 1 / 30240 =0.000033

2) If digits can repeat an zero is no one of the digits, the number of possible variations is 9x9x9x9x9 = 9^5 = 59,049.

The probaility of guessing is 1/59,049 = 0.000017