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2 years ago

10

Karina and perry are cleaning up litter in the park for community service hours. Karina and perry both claim they have covered t

he greatest area. Who is correct? Use mathematical reasoning

1 answer:

ddd [48]2 years ago

7 0

Answer:

Karina is correct

Step-by-step explanation:

<em>See attached</em>

<u>Area that Karina cleaned up:</u>

1/2*(6-0)(9-2) = 1/2*6*7 = 21

<u>Area that Petty cleaned up:</u>

2*9 = 18

As we see Karina cleaned up more area than Petty, so she is correct

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Ashley’s math average decreased 12 points to 78. Then she completed an extra credit assignment and raised her final average by 5

andriy [413]

What was her starting average? 93 points

How much did her average increase or decrease, overall? 5 points

What was her final average? 83 points

3 0

2 years ago

Read 3 more answers

From Statistics and Data Analysis from Elementary to Intermediate by Tamhane and Dunlop, pg 265. A thermostat used in an electri

Leviafan [203]

Answer:

$t=\frac{201.77-200}{\frac{2.41}{\sqrt{10}}}=2.32$

The degrees of freedom are given by:

$df=n-1=10-1=9$

The p value for this case is given by:

$p_v =2*P(t_{(9)}>2.32)=0.0455$

For this case since the p value is lower than the significance level we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly different from 200 F.

Step-by-step explanation:

Information given

data: 202.2 203.4 200.5 202.5 206.3 198.0 203.7 200.8 201.3 199.0

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

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

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

$\bar X=201.77$ represent the sample mean

$s=2.41$ represent the sample standard deviation

$n=10$ sample size

$\mu_o =200$ represent the value that we want to test

$\alpha=0.05$ represent the significance level for the hypothesis test.

t would represent the statistic

$p_v$ represent the p value for the test

Hypothesis to test

We want to determine if the true mean is equal to 200, the system of hypothesis are :

Null hypothesis: $\mu = 200$

Alternative hypothesis: $\mu = 200$

The statistic for this case is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

The statistic is given by:

$t=\frac{201.77-200}{\frac{2.41}{\sqrt{10}}}=2.32$

The degrees of freedom are given by:

$df=n-1=10-1=9$

The p value for this case is given by:

$p_v =2*P(t_{(9)}>2.32)=0.0455$

For this case since the p value is lower than the significance level we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly different from 200 F.

4 0

2 years ago

Which product is negative? (Negative StartFraction 3 over 8 EndFraction) (Negative StartFraction 5 over 7 EndFraction) (one-four

nasty-shy [4]

Answer:

$(D)\left(-\dfrac38\right)\left(-\dfrac57\right)\left(-\dfrac14\right)$

Step-by-step explanation:

The given options are:

$(A)\left(-\dfrac38\right)\left(-\dfrac57\right)\left(\dfrac14\right)\\(B)\left(\dfrac38\right)\left(-\dfrac57\right)\left(-\dfrac14\right)\\(C)\left(\dfrac38\right)\left(\dfrac57\right)\left(\dfrac14\right)\\(D)\left(-\dfrac38\right)\left(-\dfrac57\right)\left(-\dfrac14\right)$

The key to determining which product is negative is to understand the rule of sign multiplication.

Now:

The product of even negative terms is positive
The product of odd negative terms is negative.
The product of positive will always be positive.

In Options A and B, the number of negative signs is even, therefore our result is positive.

In option C, all the terms are positive, therefore our result will be positive.

In Option D, the number of negative signs is odd, therefore our result is negative.

4 0

1 year ago

Read 2 more answers

Use the appropriate normal distribution to approximate the resulting binomial distributions. A convenience store owner claims th

Naddika [18.5K]

Answer:

0.9256

Step-by-step explanation:

Given that a convenience store owner claims that 55% of the people buying from her store, on a certain day of the week, buy coffee during their visit

Let X be the number of customers who buy from her store, on a certain day of the week, buy coffee during their visit

X is Binomial (35, 0.55)

since each customer is independent of the other and there are two outcomes.

By approximation to normal we find that both np and nq are >5.

So X can be approximated to normal with mean = np = 19.25

and std dev = $\sqrt{npq} \\=2.943$

Required probability = prob that fewer than 24 customers in the sample buy coffee during their visit on that certain day of the week

= $P(X$ (after effecting continuity correction)

= 0.9256

6 0

1 year ago

Sum of positive roots of the equation (x2 - 12x + 35) (x2 + 10x + 24) = 504 is

Digiron [165]

Answer:

(3)11

Step-by-step explanation:

We are given that

$(x^2-12x+35)(x^2+10x+24)=504$

We have to find the sum of positive roots of the equation.

$x^2(x^2+10x+24)-12x(x^2+10x+24)+35(x^2+10x+24)=504$

$x^4+10x^3+24x^2-12x^3-120x^2-288x+35x^2+350x+840=504$

$x^4-2x^3-61x^2+62x+840-504=0$

$x^4-2x^3-61x^2+62x+336=0$

Factor of 336

2,3,4,6,8,7,

Let x=2

$2^4-2^4-61(2^2)+62(2)+336\neq0$

x=2 is not the root of equation

x=-2

$(-2)^4-2(-2)^3-61(-2)^2+62(-2)+336=0$

Hence x=-2 is the root of equation.

x+2 is a factor of equation.

x=3

$3^4-2(3^3)-61(3^2)+62(3)+336=0$

Therefore, x=3 is the root of equation.

$(x+2)(x-3)(x^2-x-56)=0$

$(x+2)(x-3)(x^2-8x+7x-56)=0$

$(x+2)(x-3)(x(x-8)+7(x-8))=0$

$(x+2)(x-3)(x-8)(x+7)=0$

$x-8=0\implies x=8$

$x+7=0\implies x=-7$

Positive roots are 3 and 8

Sum of positive roots=3+8=11

Option (3) is true.

4 0

1 year ago