What is the answer to 2.5d + 7.5 = 20

What is the range for 31,39,29,34,37,24,36,33,34,28

The number if marbles of different colors stored in a hat is listed below: 4 red marbles 10 green marbles 7 blue marbles. without looking in the hat, dan takes out a marble at random. he replaces the marble and then takes out another marble from the hat. what is the probability that dan takes out a blue marble in both draws?

Which of the following vectors are orthogonal to (2,1)? check all that apply