HELP! I will report you if you give a bs answer :)

19. A certain chain saw requires a fuel mixture of 5.5% oil and the remainder gasoline. How many liters of 2.5% mixture and how many of 9% mixture must be combined to produce 40.0 liters of 5.5% mixture?

A. 12 4/23 liters of 2.5% and 28 19/23 liters of 9%
B. 28 19/23 liters of 2.5% and 12 4/23 liters of 9%
C. 21 liters of 2.5% and 18 liters of 9%
D. 18 6/13 liters of 2.5% and 21 7/13 liters of 9%
E. 21 7/13 liters of 2.5% and 18 6/13 liters of 9%
F. 18 7/13 liters of 2.5% and 21 6/13 liters of 9%

20. Mary can row at the rate of 4 miles per hour in still water. Rowing downstream in a river, she can travel 3 times as far in 1 hour as she can rowing upstream. What is the rate of flow in the river?

A. 1 miles per hour
B. 2.5 miles per hour
C. 4 miles per hour
D. 2 miles per hour
E. 3.5 miles per hour
F. 3 miles per hour

a) one student is chosen from classroom a, then a student is chosen from classroom b.  

step-by-step explanation:

independent events are ones in which the probability of one event does not affect the probability of the second event.

one student is chosen from classroom a; this does not affect the chances of choosing a student from classroom b.   this makes these independent events.

when one card is chosen from a standard deck and then set aside before a second card is chosen, the probability of the second card being chosen changes.   this makes them dependent events.

when one student is chosen from classroom a and then a second student is chosen from classroom a, the probability of choosing the second student changes.   this makes them dependent events.

when a letter is chosen from the alphabet and then a second letter is chosen, the probability of choosing the second letter changes.   this makes them dependent events.

idk

step-by-step explanation:

5050

hope this !