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3 years ago

Exponential form of 81/625

Mathematics

1 answer:

Vesnalui [34]3 years ago

4 0

Step-by-step explanation:

Hey, there!!

you number is: 81/625

We know that,

81=9×9

and

625=25×25

and............................................................

9×9 means 9^2

and 25×25 means 25^2

so, the exponential form of the question is,

= $\frac{ {9}^{2} }{ {25}^{2} }$

{we simply find exponential form by finding their fraction}

Hope it helps...

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Please help with this math question

Ymorist [56]

Area of the rectangle minus area of 2 circles

Area of rectangle is 8x16
Area of circle is pi•r^2 = 3.14 x 4^2= 3.14•16

Answer is:
128 - 2(3.14•16) square inches

3 0

3 years ago

A survey report states that 70% of adult women visit their doctors for a physical examination at least once in two years. If 20

irakobra [83]

Answer:

a) 0.3921 = 39.21% probability that fewer than 14 of them have had a physical examination in the past two years.

b) 0.107 = 10.7% probability that at least 17 of them have had a physical examination in the past two years.

Step-by-step explanation:

For each women, there are only two possible outcomes. Either they visit their doctors for a physical examination at least once in two years, or they do not. The probability of a woman visiting their doctor at least once in this period is independent of any other women. This means that we use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

70% of adult women visit their doctors for a physical examination at least once in two years.

This means that $p = 0.7$

20 adult women

This means that $n = 20$

(a) Fewer than 14 of them have had a physical examination in the past two years.

This is:

$P(X < 14) = 1 - P(X \geq 14)$

In which

$P(X \geq 14) = P(X = 14) + P(X = 15) + P(X = 16) + P(X = 17) + P(X = 18) + P(X = 19) + P(X = 20)$

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 14) = C_{20,14}.(0.7)^{14}.(0.3)^{6} = 0.1916$

$P(X = 15) = C_{20,15}.(0.7)^{15}.(0.3)^{5} = 0.1789$

$P(X = 16) = C_{20,16}.(0.7)^{16}.(0.3)^{4} = 0.1304$

$P(X = 17) = C_{20,14}.(0.7)^{17}.(0.3)^{3} = 0.0716$

$P(X = 18) = C_{20,18}.(0.7)^{18}.(0.3)^{2} = 0.0278$

$P(X = 19) = C_{20,19}.(0.7)^{19}.(0.3)^{1} = 0.0068$

$P(X = 20) = C_{20,20}.(0.7)^{20}.(0.3)^{0} = 0.0008$

$P(X \geq 14) = P(X = 14) + P(X = 15) + P(X = 16) + P(X = 17) + P(X = 18) + P(X = 19) + P(X = 20) = 0.1916 + 0.1789 + 0.1304 + 0.0716 + 0.0278 + 0.0068 + 0.0008 = 0.6079$

$P(X < 14) = 1 - P(X \geq 14) = 1 - 0.6079 = 0.3921$

0.3921 = 39.21% probability that fewer than 14 of them have had a physical examination in the past two years.

(b) At least 17 of them have had a physical examination in the past two years

$P(X \geq 17) = P(X = 17) + P(X = 18) + P(X = 19) + P(X = 20)$

From the values found in item (a).

$P(X \geq 17) = P(X = 17) + P(X = 18) + P(X = 19) + P(X = 20) = 0.0716 + 0.0278 + 0.0068 + 0.0008 = 0.107$

0.107 = 10.7% probability that at least 17 of them have had a physical examination in the past two years.

6 0

3 years ago

An article estimates, with 90% confidence, that the proportion of elementary school teachers who are female is 82%. The article

GREYUIT [131]

Answer: (80% , 85%)

Step-by-step explanation:

We know that, confidence interval for population proportion is given by :-

(p-E , p+E)

, where p = sample proportion , E = Margin of error.

Given : Proportion of elementary school teachers who are female = 82%.

The article also states the maximum error of their estimate = 3%.

Then, the 90% confidence interval for the proportion of elementary school teachers who are female will be :

(82%-2% , 82%+3%)

= (80% , 85%)

Hence, the resulting 90% confidence interval for the proportion of elementary school teachers who are female = (80% , 85%)

5 0

3 years ago

Select the best answer for the question.

BlackZzzverrR [31]

Upon asking I got the rest of the information needed to answer this question.

-> Which one becomes a repeating decimal?

Your answer is D. 1/9.

1/9 = 0.111111111111111111111111111111111 ... or 0.1 repeating. It can be written with a line over the 1 asyou can see in the attached.

This means that D is the answer to your question.

7 0

2 years ago

A 17.2 gallon gasoline tank is 1/2 full. How many gallons will it take to fill the tank?

love history [14]

Answer:

8.6

Step-by-step explanation:

We know that the tank is filled halfway, and it can hold 17.2 gallons, so we can just divide to figure out how much is half the tank (the amount we need to fill it)

17.2 / 2 = 8.6

We can check our work by multiplying

8.6 x 2 = 17.2

So it would take 8.6gal to fill it up. I hope this helps :)

3 0

3 years ago