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3 years ago

Two less than thrice a number is 2 more than two third of

Mathematics

1 answer:

harkovskaia [24]3 years ago

8 0

Step-by-step explanation:

Let the two numbers be x and y.

$\therefore \: 3x - 2 = \frac{2}{3} y + 2 \\ \\ \therefore \: 3x - \frac{2}{3} y = 2 + 2\\ \\ \therefore \: 3x - \frac{2}{3} y = 4 \\ \\ \therefore \: 9x - 2y = 12$

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8 times the difference of 2 and a number

ankoles [38]

Hello There!

It would be 8(2-x)

Hope This Helps You!
Good Luck :)

- Hannah ❤

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3 years ago

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One population proportion test: Which of the following situations involves testing a claim about a single population proportion?

xenn [34]

Answer:

A recent report estimated that 25% of all college students in the United States have a sexually transmitted disease (STD). The director of the campus health center believes that the proportion of students with STDs is higher at their campus.

According to the American Heart Association guidelines, the daily maximum amount of sugar a teenager should have is 4 teaspoons. The parents of a local high school have expressed concerns that the average daily sugar intake of their students is higher than these guidelines and have been pressuring school officials to limit unhealthy snack and beverage choices offered in the cafeteria and student store.

Step-by-step explanation:

The first two researches involve the single sample compared to mean of population.

The 3rd and 4th research involves comparing samples of men and women that is two individual groups.

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3 years ago

Cory earns $52.00 in 7 hours find the unit rate answer key

MaRussiya [10]

Answer:

about $7.43 per hour

Step-by-step explanation:

52/7 = 7.43

6 0

3 years ago

The temperature, H, in °F, of a cup of coffee t hours after it is set out to cool is given by the following equation. H = 70 + 1

Alex73 [517]

Answer:

The temperature a t = 0 is 190 °F

The temperature a t = 1 is 100 °F

The temperature a t = 2 is 77.5 °F

It takes 1.5 hours to take the coffee to cool down to 85°F

It takes 2.293 hours to take the coffee to cool down to 75°F

Step-by-step explanation:

We know that the temperature in °F, of a cup of coffee t hours after it is set out to cool is given by the following equation:

$H(t)=70+120(\frac{1}{4})^t$

a) To find the temperature a t = 0 you need to replace the time in the equation:

$H(0)=70+120(\frac{1}{4})^0\\H(0)=70+120\cdot 1\\H(0) = 70+120\\H(0)=190 \:\°F$

b) To find the temperature after 1 hour you need to:

$H(1)=70+120(\frac{1}{4})^1\\H(1)=70+120(\frac{1}{4})\\H(1) = 70+30\\H(1)=100 \:\°F$

c) To find the temperature after 2 hours you need to:

$H(2)=70+120(\frac{1}{4})^2\\H(2)=70+120(\frac{1}{16})\\H(2) = 70+\frac{15}{2} \\H(2)=77.5 \:\°F$

d) To find the time to take the coffee to cool down $85 \:\°F$ , you need to:

$85 = 70+120(\frac{1}{4})^t\\70+120\left(\frac{1}{4}\right)^t=85\\70+120\left(\frac{1}{4}\right)^t-70=85-70\\120\left(\frac{1}{4}\right)^t=15\\\frac{120\left(\frac{1}{4}\right)^t}{120}=\frac{15}{120}\\\left(\frac{1}{4}\right)^t=\frac{1}{8}$

$\mathrm{If\:}f\left(x\right)=g\left(x\right)\mathrm{,\:then\:}\ln \left(f\left(x\right)\right)=\ln \left(g\left(x\right)\right)$

$\ln \left(\left(\frac{1}{4}\right)^t\right)=\ln \left(\frac{1}{8}\right)$

$\mathrm{Apply\:log\:rule}=\log _a\left(x^b\right)=b\cdot \log _a\left(x\right)$

$t\ln \left(\frac{1}{4}\right)=\ln \left(\frac{1}{8}\right)$

$t=\frac{\ln \left(\frac{1}{8}\right)}{\ln \left(\frac{1}{4}\right)}\\t=\frac{3}{2} = 1.5 \:hours$

e) To find the time to take the coffee to cool down $75 \:\°F$ , you need to:

$75=70+120\left(\frac{1}{4}\right)^t\\70+120\left(\frac{1}{4}\right)^t=75\\70+120\left(\frac{1}{4}\right)^t-70=75-70\\120\left(\frac{1}{4}\right)^t=5\\\left(\frac{1}{4}\right)^t=\frac{1}{24}$

$\ln \left(\left(\frac{1}{4}\right)^t\right)=\ln \left(\frac{1}{24}\right)\\t\ln \left(\frac{1}{4}\right)=\ln \left(\frac{1}{24}\right)\\t=\frac{\ln \left(24\right)}{2\ln \left(2\right)} \approx = 2.293 \:hours$

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3 years ago

Write an appropriate direct variation equation if y = 8 when x = 4.

Snowcat [4.5K]

$\bf \qquad \qquad \textit{direct proportional variation} \\\\ \textit{\underline{y} varies directly with \underline{x}}\qquad \qquad y=kx\impliedby \begin{array}{llll} k=constant\ of\\ \qquad variation \end{array} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ \textit{we know that } \begin{cases} y=8\\ x=4 \end{cases}\implies 8=k4\implies \cfrac{8}{4}=k\implies 2=k \\\\[-0.35em] ~\dotfill\\\\ ~\hfill y=2x~\hfill$

7 0

3 years ago

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