A chemical company makes two brands of antifreeze. The first brand is 45% pure antifreeze, in the second brand is 70% pure antifreeze. in order to obtain 90 gallons of a mixture that contains 60% of pure antifreeze, how many gallons of each brand of antifreeze must be used?

No matter what I do, I cannot figure out this problem.

The blue whale is the largest animal living on the earth. the average blue whale measures 100 feet long (30 meters) and weighs 300,000 pounds (136,000 kilograms). a whale’s head is 1⁄3 of the length of its body. a new baby whale is 1⁄4 the length of a grown whale. the average man is 1⁄17 the length of a blue whale, and 1⁄1,818 its weight. a human baby measures 1⁄4 of the length of an adult. calculate the following information: how long is a whale’s head? how long is a new baby whale? how tall is the average man? how much does the average man weigh? how tall is the average human baby?

Which measure is equivalent to 110 ml? 0.0110 l 0.110 l 1.10 l 11,000 l

The party planning committee has to determine the number of tables needed for an upcoming event. if a square table can fit 8 people and a round table can fit 6 people, the equation 150 = 8x + 6y represents the number of each type of table needed for 150 people.