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3 years ago

The birth rate in an area is increasing 6% per annum. If there 20,000 children born in this area 2009 how many will be in 2018?

Mathematics

1 answer:

Harrizon [31]3 years ago

7 0

Answer:

Step-by-step explanation:

Compound increase

20,000 x 1.06 to power of 9 = 33789 <u><em>OR</em></u> 33790

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increase by 6% 9 years

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I’m having a hard time understanding substitution. Please help!

Vikentia [17]

$b_1=\frac{2A}{h}-b_2$

Step-by-step explanation:

Given expression is;

$A=\frac{h(b_1+b_2)}{2}$

Solving for $b_1$

Multiplying both sides by 2

$2*A=\frac{h(b_1+b_2)}{2}*2\\2A=h(b_1+b_2)$

Dividing both sides by h

$\frac{2A}{h}=\frac{h(b_1+b_2)}{h}\\\frac{2A}{h}=b_1+b_2$

Subtracting $b_2$ from both sides

$\frac{2A}{h}-b_2=b_1+b_2-b_2\\\frac{2A}{h}-b_2=b_1\\b_1=\frac{2A}{h}-b_2$

$b_1=\frac{2A}{h}-b_2$

Keywords: division, subtraction

Learn more about subtraction at:

#LearnwithBrainly

3 0

3 years ago

3. If 3, x, y, 18, are in arithmetic progression, (A, P) find the value of x and y

Luba_88 [7]

Answer:

Below in bold

Step-by-step explanation:

The sequence is:

3, x, y, 18

If this is an A P then

x - 3 = y - x

2x - y = 3 (A) and

y - x = 18 - y

2y - x = 18 (B)

Multiply (A) by 2:

4x - 2y = 6 (C)

Adding B and C:

3x = 24

x = 8.

and

2y - 8 = 18

2y = 26

y = 13.

So x = 8 and y = 13.

b) ar + ar^2 = 6ar^3 where a = first term and r = common ratio

Divide by a:

r + r^2 = 6r^3

6r^3 - r^2 - r = 0

r(6r^2 - r - 1) = 0

r(3r + 1)(2r - 1) = 0

So the 2 possible values of r

= -1/3 and 1/2.

i) The common ratio is positive so it must be 1/2.

Second term ar = 8

1/2 a = 8

a = 16.

So the first 6 terms are:

16, 8, 4, 2, 1, 1/2.

5 0

2 years ago

Help im new and need help please the thing is 9.9 x 7 =__._ help please

Bezzdna [24]

Answer:

69.3 is the answer

{ Hello and welcome to Brainly :) i hope i helped }

6 0

2 years ago

Read 2 more answers

The quality control manager of a chemical company randomly sampled twenty 100-pound bags of fertilizer to estimate the variance

lisabon 2012 [21]

Answer:

The 95% confidence interval for the variance in the pounds of impurities would be $3.829 \leq \sigma^2 \leq 14.121$ .

Step-by-step explanation:

1) Data given and notation

$s^2 =6.62$ represent the sample variance

s=2.573 represent the sample standard deviation

$\bar x$ represent the sample mean

n=20 the sample size

Confidence=95% or 0.95

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

The Chi square distribution is the distribution of the sum of squared standard normal deviates .

2) Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

On this case the sample variance is given and for the sample deviation is just the square root of the sample variance.

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=20-1=19$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical values.