Help me please desperate!!!

Write a real-world word problem that can be solved by adding 34.99 and 5.79. then solve

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?

What properties allow transformation to be used as a problem solving tool