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3 years ago

What is the 18th term of the arithmetic

Mathematics

1 answer:

Irina18 [472]3 years ago

3 0

Answer:

-66

Step-by-step explanation:

a1 = 2

n = 18

d = - 4

a18 = a1 + (n - 1) * d

a18 = 2 + (18 - 1)*(-4)

a18 = 2 + 17*-4

a18 = 2 - 68

a18 = -66

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In a art class, there are 32 pens to 40 brushes what is the ratio of pens to brushes written as a fraction in simplest form ?

kolezko [41]

32/40 is the fraction to 32:40 and if u simplify it, it would be 4/5

4 0

4 years ago

What is 1 1/2 - 3 5/7?

kramer

The answer is -2.21428571429

3 0

3 years ago

Which number produces an irrational number when multipled by 1/4

BabaBlast [244]

Answer: Any irrational number

Step-by-step explanation:

An irrational number is a number that cannot be expressed as a fraction of two integers where the denominator is different from zero, it is also characterized by the fact that its decimal expression is neither exact nor periodic.

As an example of this we have $\pi = 3.141592653 ...$

On the other hand, it is necessary to know the following:

-The multiplication of two rational numbers results in a rational number.

-The multiplication of a rational number by any irrational number results in an irrational number.

This means that if we multiply 1/4 (which is rational) by any irrational number, the result will be irrational.

Therefore, the answer is: Any irrational number.

6 0

3 years ago

Construct a 99% confidence interval for the population mean, mu. Assume the population has a normal distribution. A group of 1

Zarrin [17]

Answer:

99% confidence interval for the population mean is [19.891 , 24.909].

Step-by-step explanation:

We are given that a group of 19 randomly selected students has a mean age of 22.4 years with a standard deviation of 3.8 years.

Assuming the population has a normal distribution.

Firstly, the pivotal quantity for 99% confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X - \mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean age of selected students = 22.4 years

s = sample standard deviation = 3.8 years

n = sample of students = 19

$\mu$ = population mean

Here for constructing 99% confidence interval we have used t statistics because we don't know about population standard deviation.

So, 99% confidence interval for the population mean, $\mu$ is ;

P(-2.878 < $t_1_8$ < 2.878) = 0.99 {As the critical value of t at 18 degree of

freedom are -2.878 & 2.878 with P = 0.5%}

P(-2.878 < $\frac{\bar X - \mu}{\frac{s}{\sqrt{n} } }$ < 2.878) = 0.99

P( $-2.878 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X - \mu}$ < $2.878 \times {\frac{s}{\sqrt{n} } }$ ) = 0.99

P( $\bar X -2.878 \times {\frac{s}{\sqrt{n} }$ < $\mu$ < $\bar X +2.878 \times {\frac{s}{\sqrt{n} }$ ) = 0.99

99% confidence interval for $\mu$ = [ $\bar X -2.878 \times {\frac{s}{\sqrt{n} }$ , $\bar X +2.878 \times {\frac{s}{\sqrt{n} }$ ]

= [ $22.4 -2.878 \times {\frac{3.8}{\sqrt{19} }$ , $22.4 +2.878 \times {\frac{3.8}{\sqrt{19} }$ ]

= [19.891 , 24.909]

Therefore, 99% confidence interval for the population mean is [19.891 , 24.909].

6 0

3 years ago

The length of a rectangle with area 38 in2 depends on its width. Write the formula that describes the length of the rectangle as

Ostrovityanka [42]

Answer:

L = 38/W

Step-by-step explanation:

The area of a rectangle is computed by multiplying length by width. For length L and width W in inches, your rectangle has area ...

A = LW

38 = LW

Then the length can be found by dividing the equation by W:

L = 38/W

8 0

3 years ago