Jon and Lexi are playing a marble game. According to their rules, 4 points are awarded for each red marble collected and 3 points are awarded for each blue marble collected. Which expression represents Jon's total score if he has r red marbles and b blue marbles? 4r − 3b
2r − 3b
4r + 3b
7rb

How do you use the elimination method for this question? explain, because i really want to understand!

Awindow washer cleans 42 windows in 2 hours. at this rate, how many windows did he clean in 180 minutes.

Mariah is randomly choosing three books to read from the following: 5 mysteries, 7 biographies, and 8 science fiction novels. which of these statements are true? check all that apply. there are 20c3 possible ways to choose three books to read. there are 5c3 possible ways to choose three mysteries to read. there are 15c3 possible ways to choose three books that are not all mysteries. the probability that mariah will choose 3 mysteries can be expressed as . the probability that mariah will not choose all mysteries can be expressed as 1 −