12. In a certain cafe, all the sandwiches and drinks are priced the

From a point on a river, two boats are driven in opposite directions, one at 9 miles per hour and the other at 6 miles per hou

natali 33 [55]

Well there can be two different solutions for this but i will choose the easier one. Obviously one requires a system of equations which obviously will involve a lot of thinking and some good algebra solving in order for them to solve.

As for hit and trial it is very easy, we can just keep adding the distance as we know they are in different directions. 9 + 6 = 15. So 15 x 2 = 30 miles. So after around 2 hours they will be 30 miles apart if they continue at the same pace.

7 0

3 years ago

A grower believes that one in five of his citrus trees are infected with the citrus red mite. How large a sample should be taken

mihalych1998 [28]

Answer:

n=6147

Step-by-step explanation:

1) Notation and definitions

$X=1$ number of citrus trees that are infected with the citrus red mite.

$n=5$ random sample taken

$\hat p=\frac{1}{5}=0.2$ estimated proportion of citrus trees that are infected with the citrus red mite.

$p$ true population proportion of citrus trees that are infected with the citrus red mite.

Me=0.01 represent the margin of error desired

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".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})$

In order to find the critical values we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . And the critical values would be given by:

$t_{\alpha/2}=-1.96, t_{1-\alpha/2}=1.96$

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.01$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

And replacing into equation (b) the values from part a we got:

$n=\frac{0.2(1-0.2)}{(\frac{0.01}{1.96})^2}=6146.56$

And rounded up we have that n=6147

5 0

4 years ago

Match the following equation to the correct situation.

makkiz [27]

Answer:

The correct answer is option B and D.

Step-by-step explanation:

A. Shawn owed 40% of his tuition bill, b, after paying $6.00

= 40%of (b-6)

B. The amount donated to the school was 40% more that $6.00.

Amount donated to the school = b

b=6+40% of b

C. The cost for a coat was 40% of the sum of b and $6.00.

= 40%(b+6)

D. Summer paid $6.00 more than 40% of b.

Amount by summer = x

= 40%b+6

4 0

3 years ago

Help me with the home work

Xelga [282]

A. 3x•11 you multiply 3 with x and get 3x and times 11
B. 3x because there are three x's so that equals 3x

7 0

3 years ago

Read 2 more answers

1- the diameter of a CD is 24 cm nearest to cm .find its upper and lower bound.

Tanya [424]

Answer:

1) Lower bound = 23.5 cm

Upper bound = 24.5 cm

2) I disagree

3) 7.88

4) 2.32

5) Ahmed = 60 kg

Jasim = 20 kg

Dalal = 100 kg

Step-by-step explanation:

1) diameter = 24 cm was rounded up to the nearest cm.

Now, usually, we round up 0.5 to the next whole number. This means that, the actual diameter is;

23.5 ≤ D < 24.5

Thus;

Lower bound = 23.5 cm

Upper bound = 24.5 cm

2) If you weigh 57g,converting to kg is 0.57 kg.

Now, this does not fall in between 56.5kg and 57.5kg given.

Thus, I disagree that your weight could be anything between 56.5kg and 57.5kg .

3) 7.875 approximated to the nearest two decimal place = 7.88

4) 2.3242900000 to the nearest 2 decimal place = 2.32

5) 180 kd shared between ahmed ,jasim and Dalal in the ratio of 3:1:5.

Total part of ratio = 3 + 1 + 5 = 9

Their respective shares are;

Ahmed = 3/9 × 180 = 60 kg

Jasim = 1/9 × 180 = 20 kg

Dalal = 5/9 × 180 = 100 kg

4 0

3 years ago