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weeeeeb [17]
3 years ago
8

By decreasing each dimension by 1 unit, the area of a rectangle deceased from 40 square feet to 28 square feet. Find the percent

decrease in area.
Mathematics
1 answer:
arsen [322]3 years ago
8 0

Answer:

30%

Step-by-step explanation:

Initial area is 40 square feet

Final area is 28 square feet

Difference between the initial and final areas will be 40-28=12 square feet

Taking the initial area as the base area and expressing the area change in percentage then the percentage decrease will be equivalent to

\frac {12\times 100}{40}=30

Therefore,  the decrease in area expressed as a percentage is equal to 30%

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attashe74 [19]
The exponential parent function is D
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3 years ago
What's the next number 2 7 8 3 12 9
puteri [66]

The <em>correct answer</em> is:

4.

Explanation:

Taking these numbers as groups of three, we have 2, 7, 8; 3, 12, 9.

In the first group, we can see that we first add 5 and then add 1.

The next group seems to start from the next consecutive number. That is, the first group starts with 2, and the next group starts with 3. The next terms in the second group are found by adding 5 to the second term of the first group (12 = 7+5) and then adding 1 to the third term of the first group (9=8+1); this is because we added 5 and added 1 previously.

Following this pattern, the next group of three would start from the next consecutive number up, 4. The next two terms would be 17 (12+5=17) and 10 (9+1=10).

7 0
3 years ago
Read 2 more answers
I need help! I forgot how to do this!! Please help!
Dovator [93]

First change the mixed fraction into an improper fraction

7 1/2 = 15/2

Next, change multiply 2 to both numerator and denominator

15 x 2 = 30

2 x 2 = 4

30/4

Each piece needs 3/4 of an inch. Divide 30 with 3

30/3 = 10

c) 10 pieces is your answer

hope this helps

8 0
2 years ago
Read 2 more answers
What is 2^5 in standard notation
elena-14-01-66 [18.8K]
2x2x2x2x2 is 2^5 in standard notation
8 0
3 years ago
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Suppose that we want to test the hypothesis with a significance level (alpha) of .05 that the climate has changed since industri
saw5 [17]

Answer: we reject the initial claim

(50. 3802, 51.6198)

Step-by-step explanation:

A)

The initial statement is that the mean temperature throughout history is 50°

This is the null hypothesis and it is denoted as H'

H': u = 50.

After taking a sample of 40 years, we realized that the mean temperature is 51°.

This is the alternative hypothesis, in contradiction to the alternative.

The alternative hypothesis is denoted as H1

H1: u > 50 ( upper tailed).

Sample size (n) = 40

Sample mean (x) = 51

Population standard deviation (σ) = 2

We use a z test to get the value of the test statistics.

We are using a z test because sample size is greater than 30 ( n = 40) and population standard deviation is given.

Z score = x - u/ (σ/√n)

Z score = 51 - 50 / (2/√40)

Z score = 1 / 0.3162

Z score = 3.16

Our level of significance is 5%, and the critical value at this level of significance is 1.645.

By comparing the z score relative to the critical value, since our z score is greater than 1.645, it implies that we are in the rejection region hence we reject the initial claim.

B)

We are to construct a 95% confidence interval for population mean temperature.

For upper limit

u = x + Zα/2 ×(σ/√n)

Where Zα/2 = 1.96 which is the critical value for a two tailed test at 5% level of significance.

For upper limit, we have that

u = 51 + 1.96 × (2/√40)

u = 51 + 1.96 (0.3162)

u = 51 + 0.6198

u = 51.6198.

For lower limit, we have that

u = 51 - 1.96 × (2/√40)

u = 51 - 1.96 (0.3162)

u = 51 - 0.6198

u = 50. 3802.

Hence the 95% confidence level for mean temperature is given as (50. 3802°, 51.6198°)

7 0
3 years ago
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