Answer:
Lavania observed 39 fruit flies after 6 days of observation
Step-by-step explanation:
Let x be the number of fruit flies on the first day of Lavania's study.
After 6 days she had nine more than five times as many fruit flies as when she began the study.
Five times as many fruit flies as when she began the study = 5x
Nine more than five times as many fruit flies as when she began the study=5x+9
The expression to find the population of fruit flies Lavania observed after 6 days is 5x+9
If she observes 20 fruit flies on the first day of the study, then x=6, then

THE SEQUENCE IS GEOMETRIC
Answer: The original price of brownie was $2.1 each.
Step-by-step explanation:
since we have given that
Let the original price will be x
Number of brownie purchased = 8
According to question , each brownie costs $0.20 less than the original price.
So, it becomes

Hence, the original price of brownie was $2.1 each.
Answer:
769 cubic ft
Step-by-step explanation:
Its volume:
Find the volume of a cylinder of radius 7 ft and length 5 ft:
The basic formula for his volume is V = πr²h. In this case, the volume is:
V = 3.14(7 ft)²(5 ft) = 769 cubic feet of water.