BMAT 2015 · Question 16 · Logic
SaveMaisy attends a small rural school with 15 other girls and 10 boys. Of the girls in the school, three older ones have younger sisters in the school, and two other girls have brothers in the school. Of the boys in the school, two older ones have younger brothers in the school, and two other boys have sisters in the school.
If there are no twins, and no family has more than two children in the school, how many of the children do not have either a brother or a sister in the school?