Need help what is the simplified form of this

Achemist has 200 ml of a 10% sucrose solution. she adds x ml of a 40% sucrose solution. the percent concentration, y, of the final mixture is given by the rational function: the chemist needs the concentration of the final mixture to be 30%. how many milliliters of the 40% solution should she add to the 10% solution to get this concentration?

Tanyss's house has 25 windows. her brother has washed 22 of the windows. what percent of the windows has her brother washed?

Francesca had 32 cups of flour and she uses 3/8. how much flour did francesca use? write the equation.