Olivia wants to learn a foreign language. To get an idea of how satisfied other students were after taking a foreign language course, she decides to take a random sample of 20 students. If Olivia randomly selects one class among all the foreign language classes taught that year, and then interviews all students in that class, the sampling method is a:

Cluster sampling method

Step-by-step explanation:

Cluster sampling is accomplished by dividing the population (students taking foreign language courses) into groups ( in this case different foreign course classes).

The groups are randomly selected (any of the foreign course class), and each element (student) in the selected clusters (class) are interviewed

mr. flanders’ class sold 47 doughnuts and   mr. rodriquez’s class sold 38 cartons of milk

step-by-step explanation:

let x be the number of doughnuts sold by mr. flanders’ class and y be the number of cartons sold by mr. rodriquez’s class.

1. together, the classes sold 85 items, then

x+y=85.

2. both classes earn earned $104.49 for their school. if doughnuts were sold for $1.35 each, then x doughnuts costed $1.35x. if cartons of milk were sold for $1.08 each, then y cartons costed $1.08y. hence,

1.35x+1.08y=104.49.

3. solve the system of two equations: