HELP WILL GIVE BRAINLIEST

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?

Having a hard time understanding this question (see attachment).

Tatiana reads 40 pages of her book every night for x number of nights. write an expression that shows the number of pages she has read