1. A certain identification number is a sequence of SIX digits.

(a) How many identification numbers are possible? ______- numbers (b) How many of them begin with either 023 or 003? _________ numbers (c) How many identification numbers are possible if no two adjacent digits are the same? (For example, 123-456 is permitted, but 123-345 is not.) _________numbers

2.Dripping wet after your shower, you have clean forgotten the combination of your lock. It is one of those "standard" combination locks, which uses a three number combination with each number in the range 0 through 39. All you remember is that the second number is either 25 or 35, while the third number ends in a 3. In desperation, you decide to go through all possible combinations using the information you remember. Assuming that it takes about 11 seconds to try each combination, what is the longest possible time you may have to stand dripping in front of your locker? _________sec

3.

A variable name in the programming language BASIC can be either a letter or a letter followed by a decimal digitthat is, one of the numbers 0, 1, . . . , 9. How many different variables are possible? __________ variables

PLEASE help. Its my last 3. Thank you. I'll give you a thumbs up.