Answer:
15x + 40 = 115
We set the equation to 115 because the total cost is $115.
We add the "+ 40" because of the $40 to rent the trailer for the day.
The 15x is because it represents the miles per hour (x) times the number of hours.
The number of hours times the charge per mile, plus the $40 to rent it, will equal $115.
Hope this helps!!
If the 26 bricks are each 7 cm, seems like multiplication or repeated addition would solve the problem. Multiplication would be faster. 26 x 7 = 182
182 cm tall.
Answer:
The sum is 493.4
Step-by-step explanation:
In order to find the value of the sum, you have to apply the geometric series formula, which is:
![\sum_{i=1}^{n} ar^{i-1} = \frac{a(1-r^{n})}{1-r}](https://tex.z-dn.net/?f=%5Csum_%7Bi%3D1%7D%5E%7Bn%7D%20ar%5E%7Bi-1%7D%20%3D%20%5Cfrac%7Ba%281-r%5E%7Bn%7D%29%7D%7B1-r%7D)
where i is the starting point, n is the number of terms, a is the first term and r is the common ratio.
The finite geometric series converges to the expression in the right side of the equation. Therefore, you don't need to calculate all the terms. You can use the expression directly.
In this case:
a=40
b= 1.005
n=12 (because the first term is 40 and the last term is 40(1.005)^11 )
Replacing in the formula:
![\frac{a(1-r^{n})}{1-r} = \frac{40(1-1.005^{12})}{1-1.005}](https://tex.z-dn.net/?f=%5Cfrac%7Ba%281-r%5E%7Bn%7D%29%7D%7B1-r%7D%20%3D%20%5Cfrac%7B40%281-1.005%5E%7B12%7D%29%7D%7B1-1.005%7D)
Solving it:
The sum is 493.4
m∠R = 27.03°
Solution:
Given In ΔQRP, p = 28 km, q = 17 km, r = 15 km
To find the measure of angle R:
Law of cosine formula for ΔQRP:
![r^{2}=p^{2}+q^{2}-2 pq \cos R](https://tex.z-dn.net/?f=r%5E%7B2%7D%3Dp%5E%7B2%7D%2Bq%5E%7B2%7D-2%20pq%20%5Ccos%20R)
Substitute the given values in the above formula.
![(15)^{2}=(28)^{2}+(17)^{2}-2 (28)(17) \cos R](https://tex.z-dn.net/?f=%2815%29%5E%7B2%7D%3D%2828%29%5E%7B2%7D%2B%2817%29%5E%7B2%7D-2%20%2828%29%2817%29%20%5Ccos%20R)
![225=784+289-952 \cos R](https://tex.z-dn.net/?f=225%3D784%2B289-952%20%5Ccos%20R)
![225=1073-952 \cos R](https://tex.z-dn.net/?f=225%3D1073-952%20%5Ccos%20R)
Switch the given equation.
![1073-952 \cos R=225](https://tex.z-dn.net/?f=1073-952%20%5Ccos%20R%3D225)
Subtract 1073 from both side of the equation.
![-952 \cos R=-848](https://tex.z-dn.net/?f=-952%20%5Ccos%20R%3D-848)
Divide by –952 on both sides.
![$ \cos R=\frac{106}{119}](https://tex.z-dn.net/?f=%24%20%5Ccos%20R%3D%5Cfrac%7B106%7D%7B119%7D)
![$ R=\cos^{-1} \left(\frac{106}{119}\right)](https://tex.z-dn.net/?f=%24%20%20R%3D%5Ccos%5E%7B-1%7D%20%5Cleft%28%5Cfrac%7B106%7D%7B119%7D%5Cright%29)
![R=27.03^\circ](https://tex.z-dn.net/?f=R%3D27.03%5E%5Ccirc)
Hence m∠R = 27.03°.
Answer:
1. Three things influence the margin of error in a confidence interval estimate of a population mean: sample size, variability in the population, and confidence level. For each of these quantities separately, explain briefly what happens to the margin of error as that quantity increases.
Answer: As sample size increases, the margin of error decreases. As the variability in the population increases, the margin of error increases. As the confidence level increases, the margin of error increases. Incidentally, population variability is not something we can usually control, but more meticulous collection of data can reduce the variability in our measurements. The third of these—the relationship between confidence level and margin of error seems contradictory to many students because they are confusing accuracy (confidence level) and precision (margin of error). If you want to be surer of hitting a target with a spotlight, then you make your spotlight bigger.