Elena says that 6% interest applied semi-annually is the same as 1% interest applied every month: She reasons they are the same because they are both a 12% nominal annual interest rate.

1. Is Elena correct that these two situations both offer a 12% nominal annual interest rate?
2. Is Elena correct that the two situations pay the same amount of interest?

A bank pays 8% nominal annual interest, compounded at the end of each month. An account starts with \$600, and no further withdrawals or deposits are made.

1. What is the monthly interest rate?
2. Write an expression for the account balance, in dollars, after one year.
3. What is the effective annual interest rate?
4. Write an expression for the account balance, in dollars, after \(t\) years.

At the end of each year, 10% interest is charged on a $500 loan. The interest applies to any unpaid balance on the loan, including previous interest.

Select all the expressions that represent the loan balance after two years if no payments are made.

Suppose \(m\) and \(c\) each represent the position number of a letter in the alphabet, but \(m\) represents the letters in the original message, and \(c\) represents the letters in a secret code.

The equation \(c = m + 7\) is used to encode a message. 

1. Write an equation that can be used to decode the secret code into the original message. 
2. What does this code say: "AOPZ PZ AYPJRF!"?