Plz help with these three questions

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?

Pam buys a sleeve of ball bearings for her skateboard. each of the bearings is 1 1/5 inches wide. the sleeve is 9 3/5 inches long. how many ball bearings are in the sleeve? show your work.

At 6 1/2 cents per pound of string beans how much does 7 pounds cost