Any baddies (boys) on rn

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?

Determine the number of girls in a math class with 87 boys if there are 25 girls for every 75 boys

Can someone check if i did this correct. it’s number 4 if you’re wondering.