If two red, five white, and three blue balls are placed in a box and one ball is randomly selected from the box, what are the odds against the ball being blue? (Enter a mathematical expression.)

Out of the 150 students at a summer camp, 72 signed up for canoeing. there were 23 students who signed up for trekking, and 13 of those students also signed up for canoeing. use a two-way table to organize the information and answer the following question: approximately what percentage of students signed up for neither canoeing nor trekking?