(a) The probability that the first grape is green is 8/23. Since Henry does not replace the first grape, the probability that the second grape is also green is 7/22. Therefore, the probability that both grapes are green is:
P(both green) = P(first green) x P(second green | first green)
P(both green) = (8/23) x (7/22)
P(both green) = 0.115
So the probability that both grapes are green is 0.115.
(b) The probability that the first grape is red is 15/23. Since Henry does not replace the first grape, the probability that the second grape is green is 8/22. Therefore, the probability that Henry eats a red grape then a green grape is:
P(red then green) = P(first red) x P(second green | first red)
P(red then green) = (15/23) x (8/22)
P(red then green) = 0.184
So the probability that Henry eats a red grape then a green grape is 0.184.