Help with those 2 pleasees<br>what does x equal on those both

A rectangular lot is bounded on one side by a river and on the other three sides by a total of 80m of fencing. Find the dimensio

vova2212 [387]

Hello,

Let 's a the width,
b the heigth

2a+b=80==>b=80-2a

Area=A(a,b)=a*b=a*(80-2a)
=-2a²+80a
=-2(a²-2*20a+20²-20²)
=-2(a-20)² +800
Area is maxi if a=20 and area max=800

5 0

2 years ago

Ming used the calculations shown to find out how much he would spend on 6 pounds of ground beef if 10 pounds of ground beef cost

Angelina_Jolie [31]

Answer:

He determined pounds per dollar by dividing 10 by 25 but wrote the unit rate as a dollar value.

Step-by-step explanation:

Given

$\frac{10\ pounds}{\$25} = \frac{10\ pounds}{25} / \frac{\$25}{25} = \frac{0.4}{1}$

$Unit\ Price = 40\ cents$

$40\ cents * 6 = \$2.40$

Required

Determine Ming's error

Ming's error is from here

$\frac{10\ pounds}{\$25} = \frac{10\ pounds}{25} / \frac{\$25}{25} = \frac{0.4}{1}$

He calculated the unit rate as pound per dollar.

So, after calculating the unit rate, the unit should be:

$Unit\ Rate = 0.4\ pound/\$$

But instead, he solved as:

$Unit\ Rate = \$0.4/ pound$

<em>Hence, (a) is correct</em>

5 0

2 years ago

Read 2 more answers

N experiment was conducted to test the effect of a new stain remover. Twenty stains were treated with stain remover A and stain

Klio2033 [76]

Answer:

For this case the statistic calculated is $t= 1.37$

$p_v =0.17$

So the p value is a very high value and using the significance level given $\alpha=0.1$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and there is enough evidence to conclude that we have a difference between the two means at 10% of significance.

Step-by-step explanation:

Data given and notation

$\bar X_{A}$ represent the mean for the sample for A

$\bar X_{B}$ represent the mean for the sample B

$s_{A}$ represent the sample standard deviation for the sample A

$s_{B}=$ represent the sample standard deviation for the sample B

$n_{A}=20$ sample size for the group poisoned

$n_{B}=20$ sample size for the group unpoisoned

t would represent the statistic (variable of interest)

Concepts and formulas to use

We need to conduct a hypothesis in order to check if the two means are equal or not , the system of hypothesis would be:

Null hypothesis: $\mu_{A} - \mu_{B} =0$

Alternative hypothesis: $\mu_{A} - \mu_{B} \neq 0$

For this case is better apply a t test to compare means, and the statistic is given by:

$t=\frac{\bar X_{A}-\bar X_{B}}{\sqrt{\frac{s^2_{A}}{n_{A}}+\frac{s^2_{B}}{n_{B}}}}$ (1)

t-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.

Calculate the statistic

For this case the statistic calculated is $t= 1.37$

Statistical decision

The significance level is 0.1 $\alpha=0.1$ , but we can calculate the p value for this test. The first step is calculate the degrees of freedom, on this case:

$df=n_{A}+n_{B}-2$

The p value on this case is given

$p_v =0.17$

So the p value is a very high value and using the significance level given $\alpha=0,1$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and there is enough evidence to conclude that we have a difference between the two means at 10% of significance.

5 0

2 years ago

Kevin gathered data from his classmates about the number of books they consulted and the total time they spent on a research pap

Irina-Kira [14]

Step-by-step explanation:

Bir abzas qurmaq üçün 5 addımdan keçək. Hər addım üçün bir izah və nümunə var. Nümunə bəndimiz kölə ruhları haqqında, Afrikalı Amerikalıların köləlik dövründə yaratdığı orijinal mahnılarla əlaqəli olacaq. Model paraqrafı fikrini sübut etmək üçün illüstrasiyadan (nümunələr verməklə) istifadə edir.

7 0

2 years ago

Read 2 more answers

A taxi cab in myrtle beach charges $2 per mile and $1 for every person. If a taxi cab ride for two people costs $12, how far did

oksian1 [2.3K]

Answer:

5 Miles

Step-by-step explanation:

5 Miles = 1 Miles = $2 X 5 = $10

1 Person = $1

Therefore 2 People = $1 X 2

7 0

2 years ago

Help with those 2 pleaseeswhat does x equal on those both