The numbers of boys and girls in a class was in the ratio 2:5. After 5 girls were transferred to another class, half of the remaining students were boys. How many more girls than boys were there in the class at first?
If there are 10 boys and 25 girls, which is a ratio of 2:5, then when 5 girls are transferred, there are 10 boys and 20 girls, meaning half of them are boys, so the class started out with 15 more girls than boys.
