P(all gumballs of the same color) = P(all red) + P(all blue) + P(all green)
Total = 21C4
P(all red) = 8C4/21C4
P(all blue) = 7C4/21C4
P(all green) = 6C4/21C4
P(all gumballs of the same color) = 8C4/21C4 + 7C4/21C4 + 6C4/21C4
P(all gumballs of the same color) = (8C4 + 7C4 + 6C4)/21C4
P(all gumballs of the same color) = 8/399
Bunuel
A gumball machine contains 21 gumballs, of which 8 are red, 7 are blue, and 6 are green. If a child buys 4 gumballs from the machine, what is the probability that the gumballs will all be of the same color?
A. 2/399
B. 4/399
C. 8/399
D. 11/399
E. 13/399
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