#### Answer

a. P(red) = 0.5 , P(green) = 0.5
P(red at sixth time) = 0.5
When 5 red balls are removed from the box,
P( red) = $\frac{5}{15}$ = 0.33
P(red at sixth time) = 0.33
c. He is wrong. The probability will remain the same. Coin tossing is mathematically equivalent to the procedure mentioned in part a.

#### Work Step by Step

a. Because no red balls are removed from the box, the probabilities remain unchanged.