For the selection to be 10, there has to be at least 3 girls. So there's a 1/4 chance of 3 girls picked, 1/4 4 girls, 1/4 5 girls and 1/4 6 girls. Because the sum of people has to be 10, if 4 girls are picked, to make 10 people there is a 1/1 chance of 6 boys. 1/4 * 1/1 = 1/4. So 1/4 chance of 4 girls and 6 boys
