72 is 40% of what number? A. 18 B. 144 C. 180 D. 280

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?

Can someone me out here number 4 plz

Factor the expression using the gcf. the expression 21m−49n factored using the gcf