Suppose that the username of myITU system must satisfy the following requirements: (i) each username must be eight to twelve characters long; (ii) each character in the username must be a letter (a-z or A-Z) or a digit (0−9); and (iii) each username must contain at least one digit (0−9). (iv) each username must start with a letter (a-z or A-Z). How many possible usernames are there for myITU system? Provide your argument to support your answer

File account.java (see previous exercise) contains a definition for a simple bank account class with methods to withdraw, deposit, get the balance and account number, and return a string representation. note that the constructor for this class creates a random account number. save this class to your directory and study it to see how it works. then write the following additional code: 1. suppose the bank wants to keep track of how many accounts exist. a. declare a private static integer variable numaccounts to hold this value. like all instance and static variables, it will be initialized (to 0, since it’s an int) automatically. b. add code to the constructor to increment this variable every time an account is created. c. add a static method getnumaccounts that returns the total number of accounts. think about why this method should be static - its information is not related to any particular account. d. file testaccounts1.java contains a simple program that creates the specified number of bank accounts then uses the getnumaccounts method to find how many accounts were created. save it to your directory, then use it to test your modified account class.

If an appliance consumes 500 w of power and is left on for 5 hours, how much energy is used over this time period? a. 2.5 kwh b. 25 kwh c. 250 kwh d. 2500 kwh

To maintain clarity and focus lighting might be needed