Question 15 • Geometry
There are 4 ways to choose the one girl and 15 ways to choose two boys, so there are 4 × 15 = 60 favorable groups. The total number of groups of 3 chosen from 10 people is 10 × 9 × 8 ÷ (3 × 2 × 1) = 120. Thus, the probability is 60 ÷ 120 = 50 percent, so the correct choice is 50 percent.
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