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3 years ago

(a) Tom says that 1/5 + 7/20 = 8/25

Mathematics

2 answers:

mezya [45]3 years ago

7 0

numerator = top part of the fraction

denominator = bottom part of the fraction

* means multiply

you can only add the numerator when the denominator is the same

cant add the denominator

denominator has to be the same

1/5 = 4/20

4/20 + 7/20 = 11/20

1 7/8 = 15/8

3/4 ÷ 15/8 =

3/4 * 8/15 =

24/60 = divide both top and bottom by 12 =

2/5

maks197457 [2]3 years ago

4 0

Step-by-step explanation:

a)1/5+ 7/20

1.find the CM of both denominators

2.multiply both the denominator and the numerator using the CM

=(1/5)×20 +(7/20)

=20/100 +35/100

since you multiply

3.Now add both numerators ( don't add the denominators)

=the answer is 55/100

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Jerome added two numbers.The sum was 83.One of the numbers was 45.What was the other number?

Sindrei [870]

To know the second number we should 83 - 45 and we get 38. Now we need to check the result.
45 +38, we'll get 83.
So the answer is correct.

83 - 45 = 38

<em><u>The answer is 38.</u></em>

6 0

4 years ago

Darcy harvest 8 3/4 acres of corn every 5/6 of an hour. How many acres per hour?

otez555 [7]

Answer:

The answer is $10\frac{1}{2}\ per\ hour.$

Step-by-step explanation:

Given:

Darcy harvest 8 3/4 acres of corn every 5/6 of an hour.

Now, to find the acres per hour it takes to harvest.

Darcy harvest = $8\frac{3}{4}=\frac{35}{4}\ acres.$

The time he took to harvest = $\frac{5}{6}\ hour.$

So, to get the acres per hour we put formula:

$Distance = \frac{35}{4}\ acres.$

$Time=\frac{5}{6}\ hour.$

$Speed=\frac{distance}{time}$

$Speed=\frac{\frac{35}{4}}{\frac{5}{6}}$

$Speed=\frac{35}{4}\times \frac{6}{5}$

$Speed=\frac{210}{20}$

$Speed=\frac{21}{2}$

$Speed=10\frac{1}{2}\ per\ hour.$

Therefore, the answer is $10\frac{1}{2}\ per\ hour.$

3 0

3 years ago

A manufacturer of a new medication on the market for Alzheimer's disease makes a claim that the medication is effective in 65% o

NeX [460]

Answer:

$z=\frac{0.639 -0.65}{\sqrt{\frac{0.65(1-0.65)}{180}}}=-0.309$

$p_v =P(z$

So the p value obtained was a very high value and using the significance level given $\alpha=0.05$ we have $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the proportion of adults with the medication was effective is not significantly less than 0.65

Step-by-step explanation:

Data given and notation

n=180 represent the random sample taken

X=115 represent the adults with the medication was effective

$\hat p=\frac{115}{180}=0.639$ estimated proportion of adults with the medication was effective

$p_o=0.65$ is the value that we want to test

$\alpha=0.05$ represent the significance level

Confidence=95% or 0.95

z would represent the statistic (variable of interest)

$p_v$ represent the p value (variable of interest)

Concepts and formulas to use

We need to conduct a hypothesis in order to test the claim that true proportion is less than 0.65.:

Null hypothesis: $p \geq 0.65$

Alternative hypothesis: $p < 0.65$

When we conduct a proportion test we need to use the z statisitc, and the is given by:

$z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}$ (1)

The One-Sample Proportion Test is used to assess whether a population proportion $\hat p$ is significantly different from a hypothesized value $p_o$ .

Calculate the statistic

Since we have all the info requires we can replace in formula (1) like this:

$z=\frac{0.639 -0.65}{\sqrt{\frac{0.65(1-0.65)}{180}}}=-0.309$

Statistical decision

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.

The significance level provided $\alpha=0.05$ . The next step would be calculate the p value for this test.

Since is a left tailed test the p value would be:

$p_v =P(z$

3 0

3 years ago

A shop produces 39 wet suits every 2 weeks. how long will it take the shop to produce 429 wet suits?

valkas [14]

429 ÷ 39= 11 11 ÷ 2= 5.5 (5 1/2) It takes 5 1/2 weeks to produce 429 wetsuits

3 0

3 years ago

Pls help!!!!!!!!!!!1

Sloan [31]

Answer:lol it's -3

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3 years ago