Ask the Olympics

The number of boys accounts for 5. Of the total chorus number of 12, 5/( 12-5) = 5/7, and 7/5 are girls.

It turns out that boys account for 5/6 of girls. Girls are boys: 6/5,

Later, there were more girls than before: 7/5-6/5 = 1/5.

The number of boys is: 3÷ 1/5= 15 (person).

The current female students are: 15×7/5=2 1 (person).