An urn contains 4 blue balls, 5 yellow balls and 7 red balls. if a single ball is selected, find the probability thet the ball is

Red?
Not blue?
blue or yellow

a) 7/16 red.

b) 5/16 + 7/16= 12/16=>3/4

c) 4/16 + 5/16 = 9/16

To find the probability of an event, we need to divide the number of favorable outcomes (the desired event) by the number of possible outcomes (the total number of balls in this case).

1. Probability of selecting a red ball:
There are 7 red balls in the urn, and the total number of balls is 4 (blue) + 5 (yellow) + 7 (red) = 16. So, the probability of selecting a red ball is 7/16.

2. Probability of not selecting a blue ball:
There are 4 blue balls in the urn, and the total number of balls is 4 (blue) + 5 (yellow) + 7 (red) = 16. So, the probability of not selecting a blue ball is 1 - (4/16) = 12/16 = 3/4.

3. Probability of selecting a blue or yellow ball:
There are 4 blue balls and 5 yellow balls in the urn, so the total number of favorable outcomes is 4 (blue) + 5 (yellow) = 9. The total number of balls is 4 (blue) + 5 (yellow) + 7 (red) = 16. So, the probability of selecting a blue or yellow ball is 9/16.