In your biology class, your final grade is based on several things: a lab score, scores on two major tests, and your score on th
e final exam. There are 100 points available for each score. However, the lab score is worth 23% of your total grade, each major test is worth 22.5%, and the final exam is worth 32%. Compute the weighted average for the following scores: 96 on the lab, 64 on the first major test, 62 on the second major test, and 69 on the final exam.
An event has probability 1 if you're certain that it will happen. You are sure to pick a marble that's either yellow, green, red, or blue. So, this probability is 1.
There are more yellow marbles than blue marbles, so it's actually more likely that you'll pick a yellow one, rather than the blue one.
The probability of picking a green marble is given by the number of green marbles divided by the total number of marbles. Compute this ratio and see what you get.
Similarly, the probability of picking a black marble is given by the number of black marbles divided by the total number of marbles. There are no black marbles, so...