PLEASDE HELP! Maria bought some books. She spent a total of $45 after a discount of $6 off of her total purchase. Each book cost $3. How many books did she buy?

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?

Determine the volume of a cylinder bucket if the diameter is 8.5 in. and the height is 11.5 in.

Eric drove 275 miles in 5 hours. at the same rate how long would it take him to drive 495 miles?