# Percentage and how to do them please plz help i don t understand percentage help

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hat the actual tax paid. (See example: http://www.csgnetwork.com/salestaxpercentcalc.html ) If I know my subtotal is: \$27.99 And my Tax Amount is:: \$1.96 How can I know that the Tax RATE is: 7.00 ?
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have done the calculus which reveals that the surface area is at a minimum when height is double the radius. I am now trying to find an equation for the relationship between the amount of wasted surface area as a percentage of the minimum surface area and the ratio between height and radius. If I were to plot it on a graph, the y axis would be the percentage of excess materials needed as a percentage of the minimum possible surface area, and the x axis would be height divided by radius. Since the surface area is minimized when height=2(radius), I know that when x=2, y=0. The website https://www.datagenetics.com/blog/august12014/index.html explains what I am trying to do quite well and shows the graph below. I am trying to find the equation for this graph, but am unsure how to go about it.
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units. Chemical Equation: Write a generic chemical equation for the dehydration of cobalt (II) chloride ∙ x hydrate (include the state symbols of the reactant and two products). [T2] Mass of Reactants and Products: a) Calculate the initial mass of the hydrated cobalt (II) chloride. [T1] b) Calculate the final mass of the anhydrous cobalt (II) chloride remaining in the cruiio8icible. [T1] c) Calculate the mass of water given off by the sample of hydrated cobalt (II) chloride. [T1] Moles of Products: a) Calculate the moles of anhydrous cobalt (II) chloride remaining in the crucible. [T1] b) Calculate the moles of water released from the hydrate. {T1] 4. Mole Ratio a) Create an experimental mole ratio between the b) and a). [T1] 5. Formula of Hydrate: State the chemical formula you have determined for this hydrate. Round the formula to the closest whole number value for x. [T1] Discussion/Conclusion Questions: [T6] Based on the chemical formula of the hydrate, calculate the percentage composition (percent by mass) of the hydrated cobalt (II) chloride. Remember to determine the percentage of each element (Co, Cl, H, and O). [T2] A possible source of systematic error in this experiment is insufficient heating. Suppose that the hydrate was not completely converted to the anhydrous form. Describe how this would affect: the calculated percent by mass of water and the experimental molecular formula (i.e. would x be higher, lower or the same). Suppose a student spilled some of the hydrated cobalt (II) chloride. Describe how this would affect the calculated percent by mass of water (would it be higher, lower or the same) and the experimental chemical formula of the hydrate. [T2]
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Since he became the president, did President Trump act with the transparency and the integrity that you expect from a president?” 675 voters responded the poll and 351 responded “YES.” Assume that 40% of the U.S. population supports Trump. a. Define a binary random variable, Y, for supporting Trump (Y=1) vs. not (Y=0). Calculate the population mean (????????) and variance (???????? 2 ) for supporting Trump. b. Calculate the sample mean ????̅ and the sample standard deviation of ????̅ (????????̅ ) for the poll. c. Calculate the standard error of ????̅ and construct a 95% confidence interval from the poll using ????̅ and its sample standard error. d. Conduct a two-sided hypothesis test at 5% significance level to determine whether 40% of the U.S. population supports Trump. State the null and the alternative hypotheses, calculate the test statistics and the associated p-value, and conclude. Is the Fox News survey reliable? Why? Why Not? e. Suppose that you wanted to design a survey that had a margin of error of at most 1%. That is: the difference between the upper bound and the lower bound of the confidence interval should be a maximum of 2 percentage points. For example, for ????̅ = 0.52 you are aiming for the 95 % CI to be [0.51 0.53]. How large should n be if the survey uses simple random sampling?
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with a mean of 25 gm and a standard deviation of 5 gm. (a) If the machine is used 500 times, approximately how many times will it be expected to dispense 30 gm or more of chilli sauce? (b) How can you decrease this number to half? Give a numerical answer. 2. StarTech manufactures re sensors. They use a protective screen for their sensors to protect it from dust. The sensor becomes useless if the thickness of the screen exceeds 0.5 mm. They outsource the production of the screen to a di erent company that claims to manufacture screens with a mean thickness of 0.3 mm and a standard deviation of 0.1 mm. (a) If 10000 screens are manufactured how many will be discarded because they are too thick? (b) If screens less than 0.2 mm are too thin to be used, what is the probability that screens manufactured by the above company will be discarded because they are too thick or too thin? Show the result on a graph. 3. The amount of time that Sam spends playing the guitar is normally distributed with a mean of 15 hours and a standard deviation of 3 hours. (a) Find the probability that he spends between 15 and 18 hours playing the guitar during a given week. (b) What is the probability that he spends less than 3 hours playing the guitar during a given week? 4. Soon after he took oce in 1963, President Johnson was approved by 160 out of a sample of 200 Americans. With growing disillusionment over his Vietnam policy, by 1968 he was approved by only 70 out of a sample of 200 Americans. (a) What is the 90% con dence interval for the percentage of all Americans who approved of Johnson in 1963? In 1968? (b) What is the 90% con dence interval for the change?
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1.AU MAT 120 Systems of Linear Equations and Inequalities Discussion

mathematicsalgebra Physics