Divide £9 in the ratio 2 : 1

Solve for c <br> c+d=15 <br> 3c+2d=36<br> WILL MARK BRAINLIEST AND MANY POINTS PLS ANSWER

klio [65]

C is 6 & d is 9

6+9=15
3(6)+2(9)=36
18 + 18 = 37

5 0

3 years ago

The runner has to race for 21km. She has to finish race before 1h 40min. What avarage speed She has to run to gain such goal?

abruzzese [7]

Answer:

The rate of the runner is 3.5 meters per second.

Step-by-step explanation:

To get this answer in meters per second, we first have to convert each of the terms into either meters or seconds. We can do that by multiplying by unit rates.

21 km * 1000 = 21,000 meters

1 hour * 3600 = 3,600 seconds

40 minutes * 60 = 2,400 seconds

Now we divide the meters by the total number of seconds to get the rate.

21,000 meters / (3,600 + 2,400) secs

21,000 meters / 6,000 secs

3.5 meters per second.

7 0

3 years ago

If y varies inversely with the square of x, and y=6 when x=4, find y when x=0.1

sergejj [24]

Answer:

9600

Step-by-step explanation:

y varies inversely with the square of x

y=k/(x^2)

for some non-zero constant k

y=6 when x=4

6=k/(4^2)

k=96

y=96/(x^2)

x=0.1

y=96/(0.1^2)

y=9600

8 0

3 years ago

Wires manufactured for use in a computer system are specified to have resistances between 0.11 and 0.13 ohms. The actual measure

Marina CMI [18]

Answer:

a) $P(0.11$

And we can find this probability with this difference and with the normal standard table or excel:

$P(-1.11$

b) $P(0.11 < \bar X < 0.13)$

And we can use the z score defined by:

$z = \frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n}}}$

And using the limits we got:

$z = \frac{0.11-0.12}{\frac{0.009}{\sqrt{4}}}= -2.22$

$z = \frac{0.13-0.12}{\frac{0.009}{\sqrt{4}}}= 2.22$

And we want to find this probability:

$P(-2.22< Z$

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Part a

Let X the random variable that represent the resitances of a population, and for this case we know the distribution for X is given by:

$X \sim N(0.12,0.009)$

Where $\mu=0.12$ and $\sigma=0.009$

We are interested on this probability

$P(0.11$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

If we apply this formula to our probability we got this:

$P(0.11$

And we can find this probability with this difference and with the normal standard table or excel:

$P(-1.11$

Part b

We select a sample size of n =4. And since the distribution for X is normal then we know that the distribution for the sample mean $\bar X$ is given by: