If a marble is randomly chosen from a bag that contains exactly 8 red marbles, 6 blue marbles, and 6 white marble, what is the probability that the marble will not be white?

1. ok, so theres 8 red marbles, 6 blue marbles, and 6 white marbles so that makes 

8 + 6 + 6 = 20 marbles in total 

the probability of the marble being white is 6/20 or 3/10 

so the probabilty of the marble NOT being white is 1 - (3/10) = 7/10 

and that matches up with choice e) 

2. so the ratio of the sides of a triangle is 12:14:15, and the second one is similar. for this one we have to set up a proportion 

since the shortest side of the second side is 8 inches, we can match it up with the shortest ratio of the first. and we kno the ratio of the longest side of the first triangle is 15, but we dont kno the the length of the longest side of the second triangle, so we can let that be our unknown, x. so the proportion we are going to set up is 

8 / 12 = x / 15 

now cross multiply 

12x = 120 

x = 10 

so the length of the longest side of the second triangle is 10 inches 

that matches up with choice b)

OR 

1. 1 - 6/20 = 1 - 3/10 = 7/10 
(e) 7/10 
 
Ideas: Use complement set. 

2. x:8 = 15:12 = 5:4 
(b) 10.0