A bag contain 20 red, 15 yellow and 25 blue balls.
Uncle K takes one ball from the bag. Find the probability
that the ball is:
Red
Yellow
Blue
Red or yellow

The probability that the ball is:

Red - 20:60 (simplified is 1:3)

Yellow - 15:60 (simplified is 1:4)

Blue - 25:60 (simplified is 5:12)

Red or yellow - 35:60 (simplified is 7:12)

answer: i think it is (1,-2)

85.560%

step-by-step explanation:

conditional probability is defined as:

p(a|b) = p(a∩b) / p(b)

in other words, the probability that a occurs, given that b has occurred = the probability that both a and b occur / the probability that b occurs.

in this example:

p(turns 64 | turns 44) = p(turns 64 & turns 44) / p(turns 44).

if someone turns 64, they must have already turned 44, so:

p(turns 64 | turns 44) = p(turns 64) / p(turns 44)

on page 42, we see that of the original 100,000, 94944 turn 44, and 81234 turn 64.   therefore:

p(turns 64 | turns 44) = 81234 / 94944

p(turns 64 | turns 44) = 0.85560