Answer: 1692
Step-by-step explanation:
Formula to find the sample size :
Given : Confidence level : 
⇒ significance level =
z-value for 90% confidence interval (using z-table)=
Prior estimate of the population proportion (p) of customers who keep up with regular vehicle maintenance is unknown.
Let we take p= 0.5
Margin of error : E= 2%=0.02
Now, the required sample size will be :
Simplify , we get
Hence, the required sample size = 1692
Answer:
Step-by-step explanation:
The equation for the first option is Y=10x + 200
The equation for the second option is Y=30x + 100
X = one month
To find when they would be the same about you have to set the equations equal to each other
10x + 200 = 30x + 100
-10x -100 -10x -100
100= 20x
5 = x
After five months she would save the same amount. To find how much is saved you have to plug in 5 for x in one of the equations. You can always double-check 5 by plugging it in both equations and making sure you get the same answer
Y= 10(5) + 200 = 250
Y= 30(5) + 100 = 250
She would have saved $250 after five months by using either method
Think it's B or A if they want it simplified.
