In a school there are w girls and x boys. y more girls and z more boys joined the school. How many girls are there in the school now?
There are w girls and x boys in the school. 

y more girls joined the school. 

There are w + y girls in the school. 

z more boys joined the school. 

There are w + y + z students in the school. 

There are w + y girls in the school.