The answer is 2. I hope this helped.
Answer:

And the best option would be:

Step-by-step explanation:
We assume that the distribution for the random variable is:

For this case we want to calculate the following probability:

And we can use the normal standard distribution or excel and we got:

And the best option would be:

Answer:
V= 105cm^3
Step-by-step explanation:
V=volume
(1/3)V+40=(5/7)V
(5/7)V-(1/3)V=40
(15/21)V-(7/21)V=40
(8/21)V=40
(21/8)(8/21)V=(21/8)(40
V=21*5
V=105 cm3
(1/3)(105)=35, 35+40=75, 75/105=15/21=5/7
Hey there, all you do is multiply 20 by 20, 20×20=400. Therefore, the answer is 400 square feet.