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3 years ago

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Phoebe runs at 12km/h and walks at 5km/h. One afternoon she ran and walked a total of 17km. If she ran for the same length of ti

me as she walked for how long did she run

1 answer:

earnstyle [38]3 years ago

3 0

If correct, it should be one hour. Maybe try and solve it yourself to see if this makes sense

Step-by-step explanation:

Assume the total trip that afternoon took t hours

12(t/2) + 5(t/2) = 17 => t = 2

So she ran for 1 hour.

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A bakery used 25% more butter this month that last month. If the bakery used 240 kilograms of butter last month, how much did it

SCORPION-xisa [38]

Answer:

300kg

Step-by-step explanation:

240(25/100)

240(.25) = 60

25% of 240 = 60, so add that 60 to get an extra 25% for this month

240 + 60 = 300

6 0

3 years ago

Read 2 more answers

find a number such that if 8 is subtracted from 9 times the number , the result is 6 more than twice the number

zheka24 [161]

Answer:

x=2

Step-by-step explanation:

let the number be x

9x-8=6+2x

9x-2x=6+8

7x=14

x=14/7

x=2

8 0

3 years ago

0.3(n-5)=0.4-0.2 solve for n!

mariarad [96]

Answer:

$n = 5.67$

Step-by-step explanation:

0.3(n-5)=0.4-0.2

0.3(n-5) = 0.2

Dividing 0.3 both side

$\frac{0.3(n-5) }{0.3} = \frac{0.2}{0.3}$

$n-5 = 0.67$

$n = 0.67+5$

$n = 5.67$

4 0

3 years ago

Find the equation of a line that is perpendicular to 4x+6y=1 and that has a greater intercept to the line 2x+3y=18

enot [183]

Answer:

2y - 3x = -15

Step-by-step explanation:

Slope of the line 4x + 6y = 1 is as shown below;

Rewrite in slope intercept form;

6y = -4x+1

y = -4x/6 + 1/6

y = -2x/3 + 1/6

mx = -2/3x

m = -2/3

The slope of the line perpendicular M = -1/(-2/3)

M = 3/2

Get the x and y intercept of 2x+3y = 18

x intercept occurs when y = 0

2x + 0 = 18

x= 18/2

x = 9

y intercept occurs when x = 0

0 + 3y = 18

3y= 18

y = 18/3

y = 6

The line passes through the point (9,6)

Write the equation in point slope form

y - y0 = m(x-x0)

y - 6 = 3/2(x-9)

2(y-6) = 3(x-9)

2y - 12 = 3x - 27

2y - 3x = -27 + 12

2y - 3x = -15

This gives the required equation

8 0

3 years ago

1) Lithium isotope rations are important to medicine, the 6Li/7Li ratio in a standard reference material was measured several ti

uysha [10]

Answer:

1) $0.0826052-2.776\frac{0.000013424}{\sqrt{5}}=0.082588$

$0.0826052+2.776\frac{0.000013424}{\sqrt{5}}=0.0826219$

b) $ME= 2.776\frac{0.000013424}{\sqrt{5}}=0.0000166653$

And we want 2/3 of the margin of error so then would be: $2/3 ME = 0.00001111$

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

And on this case we have that ME =0.00001111016 and we are interested in order to find the value of n, if we solve n from equation (1) we got:

$n=(\frac{z_{\alpha/2} s}{ME})^2$ (2)

Replacing we got:

$n=(\frac{2.776(0.000013424)}{0.00001111})^2 =11.25 \approx 12$

So the answer for this case would be n=12 rounded up to the nearest integer

Step-by-step explanation:

Information given

0.082601, 0.082621, 0.082589, 0.082617, 0.082598

We can calculate the sample mean and deviation with the following formulas:

$\bar X= \frac{\sum_{i=1}^n X_i}{n}$

$s = \sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}$

$\bar X=0.0826052$ represent the sample mean

$\mu$ population mean

s=0.000013424 represent the sample standard deviation

n=5 represent the sample size

Part 1

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

The degrees of freedom, given by:

$df=n-1=5-1=4$

The Confidence level is 0.95 or 95%, and the significance would be $\alpha=0.05$ and $\alpha/2 =0.025$ , the critical value would be using the t distribution with 4 degrees of freedom: $t_{\alpha/2}=2.776$

Now we have everything in order to replace into formula (1):

$0.0826052-2.776\frac{0.000013424}{\sqrt{5}}=0.082588$

$0.0826052+2.776\frac{0.000013424}{\sqrt{5}}=0.0826219$

Part 2

The original margin of error is given by:

$ME= 2.776\frac{0.000013424}{\sqrt{5}}=0.0000166653$

And we want 2/3 of the margin of error so then would be: $2/3 ME = 0.00001111$

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

And on this case we have that ME =0.00001111016 and we are interested in order to find the value of n, if we solve n from equation (1) we got:

$n=(\frac{z_{\alpha/2} s}{ME})^2$ (2)

Replacing we got:

$n=(\frac{2.776(0.000013424)}{0.00001111})^2 =11.25 \approx 12$

So the answer for this case would be n=12 rounded up to the nearest integer

3 0

3 years ago