Question

A passcode is made of 5 digits. How many maximum numbers of ways incorrect passcode is entered?

(a) 27215

(b) 50399

(c) 99999

(d) 89999

The question was posed to me in class test.

This question is from Fundamental Principle of Counting in portion Permutations and Combinations of Mathematics – Class 11

Answer 1

Correct answer is (c) 99999

For explanation I would say: Total digits are 0-9 i.e.10. In passcode, 0 may also occur at first place.

All places are filled in 10 ways.

So, by the fundamental principle of counting, total numbers possible are 10*10*10*10*10=100000.

Maximum number of incorrect pass code entered = 100000-1 = 99999.