Hi can you me and show work i don’t understand it and it’s college algebra 2

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?

I’m confused on how to work the pie charts

Ntriangle abc, m∠a = 35° and m∠b = 40°, and a=9. which equation should you solve to find b?