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The difference of 2 numbers is 21 and the quotient of the equation is 4 then what are the two numbers?

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?

One of the same side angles of two parallel lines is 20° smaller than the other one. find the measures of these two angles.