Write a C++ declaration statement for each of the following:

1. Declare a variable to store the average test scores for a class
2. Declare a variable to store a student's letter grade test score (E.g. A, B, C, etc.
3. Declare a variable to store the sale tax rate of 15%.
4. Declare a constants to store the normal body temperature of 98.6 Fahrenheit.
5. Declare a variable to store the age of each member of a church.