At his college, Jason can take a maximum of 21 hours each semester between elective classes and core classes. Each elective class costs $225 per semester hour and each core class costs $275 per semester hour. If he cannot spend more than $6,000 each semester on classes, which system of inequalities below can be used to determine the number of elective classes, e, and the number of core classes, c, he can take each semester?
A.
e + c < 21
$225e + $275c > $6,000

B.
e + c < 21
$225e + $275c < $6,000

C.
e + c > 21
$225e + $275c > $6,000

D.
e + c < 21

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?

The random variable x is the number of occurrences of an event over an interval of ten minutes. it can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. it is known that the mean number of occurrences in ten minutes is 5.3. the appropriate probability distribution for the random variable

Jack has a piece of red ribbon that is two times as long as his piece of blue ribbon. he says that he can use two different equation to find out how long his piece of red ribbon is compared to his piece of blue ribbon is. is he correct? explain his reasoning