Please help will mark brainliest

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?

Answer this question! 30 points and brainliest! only if you know the answer.

You paid 28.00 for 8 gallons of gasoline. how much would you pay for 15 gallons of gasoline?