Correct Answer - Option 2 : 3276000
Given:
In licence key 4 place for digits and 2 places for alphabet
Calculation:
There are 6 places to fill
In one place 26 alphabets are possible
in another place, 25 alphabets are possible since one alphabet is already used
Two places of the alphabet can be filled in (out of 26 alphabets) = 26 × 25 = 650
the number used in one place cannot be used in other
Four places of digits can be filled in (out of 10 digits) = 10 × 9 × 8 × 7 = 5040
∴ In 3276000 ways software license key can be made if each key contains 4 different digits followed by 2 different alphabet
