To conduct an experiment, researches randomly select six students from a class of 20. How many different groups of six students are possible?

3.33

Step-by-step explanation:

20 divided by 6 equals 3.33333333333

Round that you get 3.33

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:

1) 2/5

2) zero=0/1

3) zero=0/2

4) -4/5

5) undefined=3/0