Answer: 2x - 55
Step-by-step explanation: x equals the unknown number
( hope it helps )
Answer: 15
Step-by-step explanation:
Given : Level of confidence = 0.90
Significance level : ![\alpha=1-0.90=0.10](https://tex.z-dn.net/?f=%5Calpha%3D1-0.90%3D0.10)
Critical value : ![z_{\alpha/2}=1.645](https://tex.z-dn.net/?f=z_%7B%5Calpha%2F2%7D%3D1.645)
Margin of error : ![E=\text{ 3 dollars}](https://tex.z-dn.net/?f=E%3D%5Ctext%7B%203%20dollars%7D)
Standard deviation: ![\sigma=\text{ 7 dollars}](https://tex.z-dn.net/?f=%5Csigma%3D%5Ctext%7B%207%20dollars%7D)
The formula to find the sample size : ![n=(\dfrac{\sigma\times z_{\alpha/2}}{E})^2](https://tex.z-dn.net/?f=n%3D%28%5Cdfrac%7B%5Csigma%5Ctimes%20z_%7B%5Calpha%2F2%7D%7D%7BE%7D%29%5E2)
![\Rightarrow n=(\dfrac{7\times(1.645)}{3})^2=14.7328027778\approx15](https://tex.z-dn.net/?f=%5CRightarrow%20n%3D%28%5Cdfrac%7B7%5Ctimes%281.645%29%7D%7B3%7D%29%5E2%3D14.7328027778%5Capprox15)
Hence, the minimum sample size needed= 15.
For each roll, we'd expect a 4 to come up 1/6 of the time
X+6=y
Y^2-x^2=84
So substitute.
Y^2-x^2=84
(X+6)^2-x^2=84
X^2+12x+36-x^2=84
12x+36=84
12x=48
X=4
So then use this value to find y by substituting.
X+6=y
4+6=y
10=y