In: Statistics and Probability
(a)
Total number of balls in the bag is
11 + 5 = 16
Out of 16 balls, 5 are white so
P(first white) = 5 /16
After first draw, out of remaining 15 balls, 11 are red so
P(Second red | first white) = 11 /15
Answer: 11 /15 = 0.7333
(b)
Even number on red balls are : 2, 4, 6, 8, 10
Even number on white balls are : 12, 14, 16
That is out of 16 balls, 8 are even numbered so the probability that both are even numbered is
Answer: 0.2333
(c)
Out of 16 balls, 5 are red and even-numbered so
P(first ball red and even-numbered) = 5 / 16
After first draw, out of 15 remaining balls 7 are even numbered so
P(second even numbered | first ball red and even-numbered) = 7 / 15
Therefore the probability that the first ball is red and even-numbered and the second ball is even numbered is
P(second even numbered and first ball red and even-numbered) =P(second even numbered | first ball red and even-numbered)* P(first ball red and even-numbered) = (7/15) * (5/16) = 0.1458
Answer: 0.1458