Trying to write an equation for line on graph without any numbers given to plug into for slope

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?

Which is the solution to the inequality? 2 3/52 1/15 b< 3 2/15 b> 3 2/15

Of the 304 people who attended a school play, 5/8 were students. how many of the people who attended were students.