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3 years ago

How do you solve -k/5 times 7/5

Mathematics

1 answer:

Firdavs [7]3 years ago

5 0

Answer:

$\frac{-7}{25}k$

Step-by-step explanation:

$\frac{-k}{5} *\frac{7}{5}$

just multiply across

-k*7=-7k

5*5=25

$\frac{-7}{25}k$

hope this helps

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A solution initially contains 200 bacteria. 1. Assuming the number y increases at a rate proportional to the number present, wri

GuDViN [60]

Answer:

1. $\frac{dy}{dt}=ky$

2.543.6

Step-by-step explanation:

We are given that

y(0)=200

Let y be the number of bacteria at any time

$\frac{dy}{dt}$ =Number of bacteria per unit time

$\frac{dy}{dt}\proportional y$

$\frac{dy}{dt}=ky$

Where k=Proportionality constant

2. $\frac{dy}{y}=kdt$ ,y'(0)=100

Integrating on both sides then, we get

$lny=kt+C$

We have y(0)=200

Substitute the values then , we get

$ln 200=k(0)+C$

$C=ln 200$

Substitute the value of C then we get

$ln y=kt+ln 200$

$ln y-ln200=kt$

$ln\frac{y}{200}=kt$

$\frac{y}{200}=e^{kt}$

$y=200e^{kt}$

Differentiate w.r.t

$y'=200ke^{kt}$

Substitute the given condition then, we get

$100=200ke^{0}=200 \;because \;e^0=1$

$k=\frac{100}{200}=\frac{1}{2}$

$y=200e^{\frac{t}{2}}$

Substitute t=2

Then, we get $y=200e^{\frac{2}{2}}=200e$

$y=200(2.718)=543.6=543.6$

e=2.718

Hence, the number of bacteria after 2 hours=543.6

4 0

3 years ago

In the United States, 35% of households own a 4K television. Suppose we take a random sample of 150 households. (a) Describe the

sattari [20]

Answer:

(a) The distribution of the sample proportion is Normal distribution.

(b) The probability that in this sample of 150 households that more than 50% own a 4K television is 0.00012.

Step-by-step explanation:

We are given that in the United States, 35% of households own a 4K television.

Suppose we take a random sample of 150 households.

Let $\hat p$ = sample proportion of households who own a 4K television.

The z-score probability distribution for sample proportion is given by;

Z = $\frac{ \hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ~ N(0,1)

where, $\hat p$ = sample proportion

p = population proportion of households own a 4K television = 35%

n = sample of households = 150

(a) The distribution of the sample proportion is related to the Normal distribution.

(b) Probability that in this sample of 150 households more than 50% own a 4K television is given by = P( $\hat p$ > 0.50)

P( $\hat p$ > 0.50) = P( $\frac{ \hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ > $\frac{ 0.50-0.35}{\sqrt{\frac{0.50(1-0.50)}{150} } }$ ) = P(Z > 3.67) = 1 - P(Z $\leq$ 3.67)

= 1 - 0.99988 = 0.00012

Now, in the z table the P(Z $\leq$ x) or P(Z < x) is given. So, the above probability is calculated by looking at the value of x = 3.67 in the z table which has an area of 0.99988.

Therefore, probability that in this sample of 150 households more than 50% own a 4K television is 0.00012.

8 0

3 years ago

The slope-intercept form given (6,-5) & perpendicular to -5x - 7y = -17.

tatuchka [14]

Answer:

$y=\dfrac{7}{5}x-\dfrac{67}{5}$

Step-by-step explanation:

Slope-intercept form of a linear equation:

$y=mx+b$

where:

m is the slope.
b is the y-intercept.

Rearrange the given equation so that it is in slope-intercept form:

$\implies -5x-7y=-17$

$\implies -7y=5x-17$

$\implies y=-\dfrac{5}{7}x+\dfrac{17}{7}$

Therefore, the slope of the given equation is -⁵/₇.

If two lines are perpendicular to each other (at right angles), the product of their slopes will be -1. Therefore, their slopes will be negative reciprocals of each other.

Therefore, the slope of the line perpendicular to the given equation is:

$\sf m=\dfrac{7}{5}$