The diagram shows a sector of a circle of radius 4 cm.<br> work out the length of the arc abc

Belen has $1.65 deducted from her allowance every time she forgets to do a

zavuch27 [327]

Answer:

9.75

Step-by-step explanation:

1.65 x5 is 8.25 then you add half of 1.65 which is .825 to get 9.75

3 0

2 years ago

2/3(12x+30)-12=0.4(15x+10)

nikdorinn [45]

Isolate the variable by dividing each side by factors that don’t contain variable.

Answer: x = -2

Hope this helps!
Have a great day!

7 0

3 years ago

Read 2 more answers

Estimate 3/8 + 3/4 + 7/8 =

goldfiish [28.3K]

Answer:

2

Step-by-step explanation:

3/8+3/4+7/8

=3/8+6/8+7/8

=16/8

=2

8 0

2 years ago

One hen lays 7 eggs in three days.<br>How many eggs do three hens lay in nine days?

kramer

Answer:

63 eggs.

Step-by-step explanation:

7 times 3 equals 21, which is the amount of eggs one chicken lays in 9 days. Multiply that by 3, you get 63.

3 0

3 years ago

Read 2 more answers

A sociologist was investigating the ages of grandparents of high school students. From a random sample of 10 high school student

umka2103 [35]

Answer:

$(69.8-71.6) -2.101 \sqrt{\frac{8.38^2}{10} +\frac{6.65^2}{10}}= -8.908$

$(69.8-71.6) +2.101 \sqrt{\frac{8.38^2}{10} +\frac{6.65^2}{10}}= 5.308$

So then the confidence interval for the difference of means is given by:

$-8.908 \leq \mu_M -\mu_F \leq 5.308$

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

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".

$\bar X_{M}= 69.8$ represent the mean for the age of grandmother

$\bar X_{F}= 71.6$ represent the mean for the age of grandfather

$s_{M}= 8.38$ represent the sample deviation for the age of grandmother

$s_{F}= 6.65$ represent the sample deviation for the age of grandfather

$n_M = n_F= 10$

Solution to the problem

For this case the confidence interval is given by:

$(\bar X_{M} -\bar X_F) \pm t_{\alpha/2} \sqrt{\frac{s^2_M}{n_M} +\frac{s^2_F}{n_F}}$

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n_M +n_F-2=10+10-2=18$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,18)".And we see that $t_{\alpha/2}=2.101$

And replacing we got:

$(69.8-71.6) -2.101 \sqrt{\frac{8.38^2}{10} +\frac{6.65^2}{10}}= -8.908$

$(69.8-71.6) +2.101 \sqrt{\frac{8.38^2}{10} +\frac{6.65^2}{10}}= 5.308$

So then the confidence interval for the difference of means is given by:

$-8.908 \leq \mu_M -\mu_F \leq 5.308$

5 0

3 years ago

The diagram shows a sector of a circle of radius 4 cm. work out the length of the arc abc