Solve the equation

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?

Find the value of the variable and the length of each secant segment.

Gabrielle's age is two times mikhail's age. the sum of their ages is 84. what is mikhail's age?