Ahhh i need helppp pls

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?

Rewrite the expression in z to the n power. the expression i was given is: 1 over z to the negative 1 half power.

Zack and tia played chess for 50 min they put the chessboard away at 11: 20 when did they start