18/30 = $0.6 per message
0.6 * 12 = 7.2
Solution: $7.20 for 12 messages
The best answer to the statistics question above would be letter A. The r-value that represents the strongest negative correlation among the given choices would be -0.7. This is because the magnitude of the correlation ranges from .7 to .9 which indicates a strong correlation. The negative sign connotes the negative relationship.
Check the picture below.
so our bases are "d" and "d+a+b", and a height of "c".
![\bf \textit{area of a trapezoid}\\\\ A=\cfrac{h(x+y)}{2}~~ \begin{cases} x,y=\stackrel{parallel~sides}{bases}\\ h~~~=height\\ \cline{1-1} x=d\\ y=d+a+b\\ h=c\\ A=(d+b)c \end{cases}\implies (d+b)c=\cfrac{c[d+(d+a+b)]}{2} \\\\\\ 2(d+b)c=c[d+(d+a+b)]\implies 2dc+2bc=c(2d+a+b)](https://tex.z-dn.net/?f=%5Cbf%20%5Ctextit%7Barea%20of%20a%20trapezoid%7D%5C%5C%5C%5C%20A%3D%5Ccfrac%7Bh%28x%2By%29%7D%7B2%7D~~%20%5Cbegin%7Bcases%7D%20x%2Cy%3D%5Cstackrel%7Bparallel~sides%7D%7Bbases%7D%5C%5C%20h~~~%3Dheight%5C%5C%20%5Ccline%7B1-1%7D%20x%3Dd%5C%5C%20y%3Dd%2Ba%2Bb%5C%5C%20h%3Dc%5C%5C%20A%3D%28d%2Bb%29c%20%5Cend%7Bcases%7D%5Cimplies%20%28d%2Bb%29c%3D%5Ccfrac%7Bc%5Bd%2B%28d%2Ba%2Bb%29%5D%7D%7B2%7D%20%5C%5C%5C%5C%5C%5C%202%28d%2Bb%29c%3Dc%5Bd%2B%28d%2Ba%2Bb%29%5D%5Cimplies%202dc%2B2bc%3Dc%282d%2Ba%2Bb%29)
![\bf ~~\begin{matrix} 2dc \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix}~~+2bc=~~\begin{matrix} 2dc \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix}~~+ac+bc\implies 2bc=ac+bc\implies 2bc=c(a+b) \\\\\\ \cfrac{2b~~\begin{matrix} c \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix}~~}{~~\begin{matrix} c \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix}~~}=a+b\implies 2b=a+b\implies 2b-b=a\implies \blacktriangleright b=a \blacktriangleleft](https://tex.z-dn.net/?f=%5Cbf%20~~%5Cbegin%7Bmatrix%7D%202dc%20%5C%5C%5B-0.7em%5D%5Ccline%7B1-1%7D%5C%5C%5B-5pt%5D%5Cend%7Bmatrix%7D~~%2B2bc%3D~~%5Cbegin%7Bmatrix%7D%202dc%20%5C%5C%5B-0.7em%5D%5Ccline%7B1-1%7D%5C%5C%5B-5pt%5D%5Cend%7Bmatrix%7D~~%2Bac%2Bbc%5Cimplies%202bc%3Dac%2Bbc%5Cimplies%202bc%3Dc%28a%2Bb%29%20%5C%5C%5C%5C%5C%5C%20%5Ccfrac%7B2b~~%5Cbegin%7Bmatrix%7D%20c%20%5C%5C%5B-0.7em%5D%5Ccline%7B1-1%7D%5C%5C%5B-5pt%5D%5Cend%7Bmatrix%7D~~%7D%7B~~%5Cbegin%7Bmatrix%7D%20c%20%5C%5C%5B-0.7em%5D%5Ccline%7B1-1%7D%5C%5C%5B-5pt%5D%5Cend%7Bmatrix%7D~~%7D%3Da%2Bb%5Cimplies%202b%3Da%2Bb%5Cimplies%202b-b%3Da%5Cimplies%20%5Cblacktriangleright%20b%3Da%20%5Cblacktriangleleft)
Answer:
The answer to your question is: 20 hours.
Step-by-step explanation:
Data
Hortencia = $350
Alex $18 / h
# hours Alex must paint to make more money than Hortencia = ?
Process
Equation 18 x n > 350
n > 350 / 18
n > 19.4 hours
If Alex work 19.4 hours, he will make the same amount of money than Hortencia, then He needs to work 20 hours.
Answer: x=4
Step-by-step explanation:
The perimeter´s formula for this kind of polygons is
The triangle perimeter would be:
(x+2)+(x+3)+(x+3)
And the rectangle:
(x+2)+(x+2)+x+x
For them to have the same value, we should equal them:
(x+2)+(x+3)+(x+3)=(x+2)+(x+2)+x+x
Working with this:
3x+8=4x+4
x=4
