Cheryl writes 7 fewer posts than Kevin on a social media site. Answer the questions to write an algebraic expression. Then evaluate the expression for the given value, 1. Choose a variable to represent the number of posts Kevin writes. Explain why you chose this variable. 2. Which operation ( addition, subtraction, multiplication, or division ) applies to this situation? Justify your choice. 3. Use your variable and the operation you identified to write an expression for the number of post Cheryl wrote. 4. If Kevin wrote 21 post, how many did Cheryl write.​

Exclude leap years from the following calculations. (a) compute the probability that a randomly selected person does not have a birthday on october 4. (type an integer or a decimal rounded to three decimal places as needed.) (b) compute the probability that a randomly selected person does not have a birthday on the 1st day of a month. (type an integer or a decimal rounded to three decimal places as needed.) (c) compute the probability that a randomly selected person does not have a birthday on the 30th day of a month. (type an integer or a decimal rounded to three decimal places as needed.) (d) compute the probability that a randomly selected person was not born in january. (type an integer or a decimal rounded to three decimal places as needed.)