Simplify (a+b) ²-2ab
1 answer:
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The password format is = inpray93
vowel , consonant, consonant, consonant, vowel, consonant, number, number.
There are 21 consonants, 5 vowels and 10 number choices (0-9)
Since, there are 21 consonants and repetition is allowed so for 2nd, 3rd, 4th, and 6th positions 21 choices are available. For 1st and 5th positions, 5 choices are available and for 7th and 8th position there are 10 choices (0 to 9).
Passwords are not case sensitive which means upper case and lower case letters are same.
So, the number of passwords can be =
= 486202500
Part (b) question is not given. But it can be opposite to the first part i.e when the password letters are case sensitive.
This means all the letters are different.
So, number of passwords will be =
= 31116960000