A four​-character password to log onto a computer is drawn from the digits​ 0-9 and a subset of 23 letters of the alphabet​ (repetition is​ permitted). Determine the number of passwords possible if
​a) the letters used are not case sensitive​ (that is, a lowercase letter is treated the same as an uppercase​ letter).
​b) the letters used are case sensitive​ (that is, an uppercase letter is considered different than the same lowercase​ letter).

Respuesta :

Answer:

a) the answer is 33*33*33*33= 1185921

b) the answer is 56*56*56*56= 9834496

Step-by-step explanation:

a) since the letters used are not case sensitive and repetition is allowed we have 33 options.

The 0-9 digits are 10 digits in total and the 23 letters gives us= 23+10= 33 options

Getting a four character password with repetition gives us

33*33*33*33= 1185921

b) The letters used are case sensitive and repetition allowed we have 56 options

23+23+10= 56

Getting a four character password

56*56*56*56= 9834496