See picture hope it helps
Is that a trick question wouldn't it be 20??? I'm confused
Answer: A. 0.50
Step-by-step explanation:
The formula to find the sample size : 
, where p= Prior estimate of population proportion.
E= Margin of error
z* =Critical z-value.
When , we do not have prior estimate of population proportion , we use p= 0.5 because at p=0.5 it gives the maximum same sample size for the corresponding confidence interval and margin of error.
Therefore , the conservative value for n can be obtained by using p=0.50.
Therefore , the correct answer is A.0.50 .
Answer:
C. Line 3
Step-by-step explanation:
First, you need to write to expressions to model each situation:
Plan A: 10+0.15x
Plan B: 30+0.1x
Next, set the expressions equal to each other and solve for x:
10+0.15x=30+0.1x
<em>*Subtract 0.1x from both sides to isolate the variable*</em>
10+0.05x=30
<em>*Subtract 10 from both sides*</em>
0.05x=20
<em>*Divide both sides by 0.05*</em>
x=400
The plans would have the same cost after 400 minutes of calls.
To find how much money the plans cost at 400 minutes, plug 400 into either expression. We'll use Plan A:
10+0.15(400)
10+60
70
The plans will cost $70.
Hope this helps!