Expand (3x)^2
When you see ^2, it means that the term(s) inside the parenthesis should be copied once, and multiplied.
(3x)^2 = (3x)(3x)
(3x)(3x) is your expanded form
<em>~Rise Above the Ordinary</em>
For margin of error to be a maximum of 3:
3 = z*(SD / sqrt(n)), where z is the z-score, SD is the standard deviation and n is the sample size.
z = 1.96 for a 95% confidence interval, and we are given SD = 15.
3 = 1.96*15/sqrt(n)
sqrt(n) = 9.8
n = 96.04 ~ 96 commercials.
Percentage of depreciation of the car that Marie bought = 15%
Present value of the car = 13000
Let us assume that the value of the car at the time of buying = x
So
The percentage valuation of the car now = (100 - 15) percent
= 85 percent
Then
(85/100) * x = 13000
85x = 13000 * 100
85x = 1300000
x = 1300000/85
= 15294.12
So the actual cost of the car is 15294.12. I hope the procedure is clear enough for you to understand.
