What is the Contra Positive to: If a figure is a Pentagon then it has 5 sides?

Me. i can't figure out this question. give an explanation too. .

Abag contains 3 red marbles, 2 blue marbles, and 2 green marbles. one marble is picked, then another marble. assume that the selections are made with replacement. a) find the probability of picking two red marbles with replacement. b) find the probability of picking a red marble and a blue marble. assume the selections are made without replacement. c) find the probability of picking two red marbles without replacement. d) find the probability of picking a red marble and a blue marble without replacement.

Which coefficient matrix represents a system of linear equations that has a unique solution ? options in photo*