Calculate the number in the middle of 2.7 and 9.5

You purchased 8 pounds 10 ounces of candy from a candy shop. you want to split it equally among 3 classrooms at a local school.

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?

Ineed to know how to write question one in mathematical terms