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valina [46]
2 years ago
15

A new crew of painters can paint a small apartment in 12 hours.  An experienced crew can paint the small apartment in 6 hours. 

How many hours does it take to paint the apartment when the two crews work together? It takes _____ hours to paint the apartment when the two crews work together
Mathematics
1 answer:
Varvara68 [4.7K]2 years ago
4 0
The new crew works at the rate 1/12 apt/hr.
The old crew works at the rate 1/6 apt/hr.

Let x = hours required to paint the apartment when the two crews work together.

That is, 
(1/12 + 1/6  apt/hr)*(x hr) = (1 apt)
(3/12)x = 1
(1/4)x = 1
x = 4 hours

Answer:  4 hours 

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What is the mixed number to 53/12
Virty [35]
The mixed number is 4 5/12.
6 0
2 years ago
ALGEBRA Jake Duffy drove 12,568 miles
kirza4 [7]

Answer:

The cost per mile that Jack Duffy charge $0.278 per miles , i.e option B  

Step-by-step explanation:

Given as :

The distance drove by Jack Duffy = d = 12,568 miles

The fixed costs totaled = $1,485.00

The variable cost totaled = $2,015.75

Let The cost per mile that Jack Duffy charge = $x cost per miles

Now, According to question

The totaled cost = The fixed costs + The variable cost

Or, The totaled cost = $1,485.00 + $2,015.75

I.e  The totaled cost = $3500.75

Now,

The cost per mile that Jack Duffy charge = \dfrac{\extrm Total cost}{\textrm Total Distance}

I.e x = \dfrac{3500.75}{12568}

∴ x = $0.278 per miles

So,The cost per mile that Jack Duffy charge = x = $0.278 per miles .

Hence,The cost per mile that Jack Duffy charge $0.278 per miles , i.e option B  Answer

5 0
2 years ago
The flower shop has 40 times as many flowers in one cooler as Julia has in her bouquet. The cooler has 120 flowers. How many flo
kiruha [24]
The answer is 4,800 if u multiply 120x40

8 0
2 years ago
Read 2 more answers
Three assembly lines are used to produce a certain component for an airliner. To examine the production rate, a random sample of
nikitadnepr [17]

Answer:

a) Reject H₀

b) [0.31; 3.35]

Step-by-step explanation:

Hello!

a) The objective of this example is to compare if the population means of the production rate of the assembly lines A, B and C. To do so the data of the production of each line were recorded and an ANOVA was run using it.

The study variable is:

Y: Production rate of an assembly line.

Assuming that the study variable has a normal distribution for each population, the observations are independent and the population variances are equal, you can apply a parametric ANOVA with the hypothesis:

H₀ μ₁= μ₂= μ₃

H₁: At least one of the population means is different from the others

Where:

Population 1: line A

Population 2: line B

Population 3: line C

α: 0.01

This test is always one-tailed to the right. The statistic is the Snedecor's F, constructed as the MSTr divided by the MSEr if the value of the statistic is big, this means that there is a greater variance due to the treatments than to the error, this means that the population means are different. If the value of F is small, it means that the differences between populations are not significant ( may differ due to error and not treatment).

The critical region is:

F_{k-1;n-k; 1-\alpha } = F_{2;15; 0.99} = 6.36

If F ≥ 3.36, the decision is to reject the null hypothesis.

Looking at the given data:

F= \frac{MSTr}{MSEr}= 11.32653

With this value the decision is to reject the null hypothesis.

Using the p-value method:

p-value: 0.001005

α: 0.01

The p-value is less than the significance level, the decision is to reject the null hypothesis.

At a level of 5%, there is significant evidence to say that at least one of the population means of the production ratio of the assembly lines A, B and C is different than the others.

b) In this item, you have to stop paying attention to the production ratio of the assembly line A to compare the population means of the production ratio of lines B and C.

(I'll use the same subscripts to be congruent with part a.)

The parameter to estimate is μ₂ - μ₃

The populations are the same as before, so you can still assume that the study variables have a normal distribution and their population variances are unknown but equal. The statistic to use under these conditions, since the sample sizes are 6 for both assembly lines, is a pooled-t for two independent variables with unknown but equal population variances.

t=  (X[bar]₂ - X[bar]₃) - ( μ₂ - μ₃) ~t_{n_2+n_3-2}

Sa√(1/n₂+1/n₃)

The formula for the interval is:

(X[bar]₂ - X[bar]₃) ± t_{n_2+n_3-2; 1 - \alpha /2}* Sa\sqrt{*\frac{1}{n_2} + \frac{1}{n_3} }

Sa^{2} = \frac{(n_2-1)*S_2^2+ (n_3-1)*S_3^2}{n_2+n_3-2}

Sa^{2} = \frac{(5*0.67)+ (5*0.7)}{6+6-2}

Sa^{2} = 0.685

Sa= 0.827 ≅ 0.83

t_{n_2+n_3-2;1-\alpha /2}= t_{10;0.995} = 3.169

X[bar]₂ = 43.33

X[bar]₃ = 41.5

(43.33-41.5) ± 3.169 * *0.83\sqrt{*\frac{1}{6} + \frac{1}{6} }

1.83 ± 3.169 * 0.479

[0.31; 3.35]

With a confidence level of 99% you'd expect that the difference of the population means of the production rate of the assemly lines B and C.

I hope it helps!

8 0
2 years ago
Six years ago, Kelsey opened a savings account that earns 1.2% simple interest every year. She started the account with $600 and
densk [106]

Answer:

600 times .012=7.20

7.20 times 6= 43.20

43.20+ 600= 643.20

the correct answer is b- $643.20

5 0
2 years ago
Read 2 more answers
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