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3 years ago

Twenty less than 8 times a number is the same as 15 more than the number

Mathematics

2 answers:

grin007 [14]3 years ago

7 0

Here is the equation :8x-20=15+x

Anestetic [448]3 years ago

4 0

This means that it is 8x-28=15+x. We let x equal the number. You can solve for the equation.

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Suppose Jamal visits a record store with 788 records. If 264 of the records are from the years 1975 to 1979 and Jamal selects a

svetoff [14.1K]

34% because to find the percentage you need to divide the amount in the time, 264, by the total amount of records, 778, and when you do that you get around .335, and convert that to a percentage you multiply it by 100, and you get 33.5%, but then you round it up to 34%.

5 0

2 years ago

For a certain river, suppose the drought length Y is the number of consecutive time intervals in which the water supply remains

AnnZ [28]

Answer:

a) There is a 9% probability that a drought lasts exactly 3 intervals.

There is an 85.5% probability that a drought lasts at most 3 intervals.

b)There is a 14.5% probability that the length of a drought exceeds its mean value by at least one standard deviation

Step-by-step explanation:

The geometric distribution is the number of failures expected before you get a success in a series of Bernoulli trials.

It has the following probability density formula:

$f(x) = (1-p)^{x}p$

In which p is the probability of a success.

The mean of the geometric distribution is given by the following formula:

$\mu = \frac{1-p}{p}$

The standard deviation of the geometric distribution is given by the following formula:

$\sigma = \sqrt{\frac{1-p}{p^{2}}$

In this problem, we have that:

$p = 0.383$

$\mu = \frac{1-p}{p} = \frac{1-0.383}{0.383} = 1.61$

$\sigma = \sqrt{\frac{1-p}{p^{2}}} = \sqrt{\frac{1-0.383}{(0.383)^{2}}} = 2.05$

(a) What is the probability that a drought lasts exactly 3 intervals?

This is $f(3)$

$f(x) = (1-p)^{x}p$

$f(3) = (1-0.383)^{3}*(0.383)$

$f(3) = 0.09$

There is a 9% probability that a drought lasts exactly 3 intervals.

At most 3 intervals?

This is $P = f(0) + f(1) + f(2) + f(3)$

$f(x) = (1-p)^{x}p$

$f(0) = (1-0.383)^{0}*(0.383) = 0.383$

$f(1) = (1-0.383)^{1}*(0.383) = 0.236$

$f(2) = (1-0.383)^{2}*(0.383) = 0.146$

Previously in this exercise, we found that $f(3) = 0.09$

$P = f(0) + f(1) + f(2) + f(3) = 0.383 + 0.236 + 0.146 + 0.09 = 0.855$

There is an 85.5% probability that a drought lasts at most 3 intervals.

(b) What is the probability that the length of a drought exceeds its mean value by at least one standard deviation?

This is $P(X \geq \mu+\sigma) = P(X \geq 1.61 + 2.05) = P(X \geq 3.66) = P(X \geq 4)$ .

We are working with discrete data, so 3.66 is rounded up to 4.

Either a drought lasts at least four months, or it lasts at most thee. In a), we found that the probability that it lasts at most 3 months is 0.855. The sum of these probabilities is decimal 1. So:

$P(X \leq 3) + P(X \geq 4) = 1$

$0.855 + P(X \geq 4) = 1$

$P(X \geq 4) = 0.145$

There is a 14.5% probability that the length of a drought exceeds its mean value by at least one standard deviation

8 0

3 years ago

The volume of a cone is 16x cubic inches, Its height is 12 inches. What is the radius of the cone?

Dimas [21]

The radius would be 2

4 0

3 years ago

HELP ME PLEASE !!!!!!!!

fredd [130]

Answer:

AB = 14

DE =7

Step-by-step explanation:

Remark

Opposite sides of a parallelogram are equal.

AB = CD

AB = 14

According to the diagram AE = 19

AD = 26 which is the same size as BC

DE = 26 - 19 = 7

DE = 7

4 0

2 years ago

A rectangular ground is 40m long 35m board 2m path is constructed inside it find its area

iren2701 [21]

Answer:

2800

Step-by-step explanation:

solution:

here,

length=40 meter

Breadth=35 meter

height=2meter

area=?

we have,

A=l×b×h

=40×35×2

=2800 ans.

4 0

2 years ago