I need some simple equations that equal 12,20,21,31.

Cara computes the mean and variance for the set 87, 46, 90, 78, and 89. She finds the mean to be 78. Her steps for finding the variance are shown below.

Look at the following number sequence. 6, 9, 12, 15,. Based on the pattern, what are the next two terms? 16, 19 21, 24 18, 21 18, 135

A man was found murdered on Sunday morning ... ? A man was found murdered on Sunday morning. His wife immediately called the police. The police questioned the wife and staff and got these alibis: The Wife said she was sleeping.

The sum of three numbers is 99. The first number is 9 more than the third. The second number is 4 times the third. What are the numbers?

We flip a fair coin 10 times. what is the probability that we get heads in at least 6 of the 10 flips?

F K = (x, y), is Set K a function?

70% of the 100 students in Middle School cafeteria bought their lunch some of the students that bought their lunch leave the cafeteria to attend an assembly now only 60% of the remaining students brought their lunch how many students are remaining

What percent of 150 equals 24.9

Raul wants to buy a new collar for each of his 3 cats. The collars come in a choice of 4 different colors. Step 2 of 2 : How many selections of collars are possible if repetitions of colors are not allowed

Need to find the side lengths for a triangle with sides a=2a, b = 3a, c = 17. need to solve for variable a and not sure how.