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3 years ago

Help with number 15 please ?!

Mathematics

2 answers:

VMariaS [17]3 years ago

7 0

Answer:

18.8

Step-by-step explanation:

Alborosie3 years ago

3 0

Answer:

Step-by-step explanation:

15)We would apply the formula for exponential growth which is expressed as

y = b(1 + r)^t

Where

y represents the population of students after t years.

t represents the number of years.

b represents the initial population of students.

r represents growth rate.

From the information given,

b = 9

r = 15% = 15/100 = 0.15

Therefore, the exponential growth function is

y = 9(1 + 0.15)^t

y = 9(1.15)^t

In 2008, t = 2008 - 2001 = 7 years

y = 9(1.15)^7

y = 24 students

16) the formula for exponential decay is expressed as

y = b(1 - r)^t

b = 24500

r = 4% = 4/100 = 0.04

Therefore, the exponential decay function is

y = 24500(1 - 0.04)^t

y = 24500(0.96)^t

In 2020, t = 2020 - 1970 = 50 years

y = 24500(0.96)^50

y = 3182 people

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maks197457 [2]

Answer:

divide by -3 and reverse it

Step-by-step explanation:

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2 years ago

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What is the value of the expression 9x1/3 to the second power + 2+4/7

wariber [46]

The expression is 9* $\frac{1}{3}^{2}$ +2+ $\frac{4}{7}$ .

9* $\frac{1}{3}^{2}$ +2+ $\frac{4}{7}$ ---> First square $\frac{1}{3}$ by squaring the top and bottom number.

=9* $\frac{1}{9}$ +2+ $\frac{4}{7}$ ---> Multiply 9 and $\frac{1}{9}$

=1+2+ $\frac{4}{7}$ ---> Add

=3 $\frac{4}{7}$ ---> Optional: turn into improper fraction

= $\frac{25}{7}$

6 0

3 years ago

Explain how to perform a two-sample z-test for the difference between two population means using independent samples with

Effectus [21]

Answer:

Z= (X1`-X2`)- (u1-u2)/ $\sqrt{ \frac{ s_1^2}{n_1^2} +\frac{ s_2^2}{n_2}$ (here s1=σ1 and s2= σ2)

Step-by-step explanation:

Let X1` be the mean of the first random sample of size n1 from a normal population with a mean u1 and known standard deviation σ1.Let X2` be the mean of the second random sample of size n2 from another normal population with a mean u2 and known standard deviation σ2. Then the sampling distribution of the difference X1`-X2` is normally distributed with a mean of u1-u2 and a standard deviation of

$\sqrt{ \frac{ s_1^2}{n_1^2} +\frac{ s_2^2}{n_2}$ . (here s1=σ1 and s2= σ2) In other words the variable

Z= (X1`-X2`)- (u1-u2)/ $\sqrt{ \frac{ s_1^2}{n_1^2} +\frac{ s_2^2}{n_2}$ (here s1=σ1 and s2= σ2)

is exactly standard normal no matter how small sample sizes are . Hence it is used as a test statistic for testing hypotheses about the difference between two population means.

The procedure is stated below.

1) Formulate the null and alternative hypotheses.

2) Decide on significance level ∝

3) Use the test statistic Z= (X1`-X2`)- (u1-u2)/ $\sqrt{ \frac{ s_1^2}{n_1^2} +\frac{ s_2^2}{n_2}$ (here s1=σ1 and s2= σ2)

4) Find the rejection region

5)Compute the value of Z from the sample data

6) Rehect H0 if Z falls in the critical region, accept H0 , otherwise.

6 0

3 years ago

Find the value c that will make 9x^2 +30x+c a perfect square trinomial

anzhelika [568]

Answer:

$c = 25$

Step-by-step explanation:

Given :-

A quadratic equation is given to us.
The equation is 9x² + 30x + c .

And we need to find out the value of c for which the given trinomial is a perfect square. On looking at the given expression all the terms are having positive signs before them .So we can rewrite it on the basis of ,

Identity :-

$\implies (a+b)^2=a^2+b^2+2ab$