Let me represent the average number of hours of sleep all the students are your school caught the previous night

What is the equation of the graph below? y=sec(x)-4

What is the result of adding the system of equations? 2x+y=4 3x-y=6

There are three bags: a (contains 2 white and 4 red balls), b (8 white, 4 red) and c (1 white 3 red). you select one ball at random from each bag, observe that exactly two are white, but forget which ball came from which bag. what is the probability that you selected a white ball from bag a?