What is –23=x–23 ? I have a problem with this question

If 400 reduced by two times my present age is 296, how old am I now?

vitfil [10]

Answer:

52 years.

Step-by-step explanation:

Represent my current age by c. Then 400 - 2c = 296, or

104 = 2c

Then c must be 104/2, or 52 years.

4 0

4 years ago

Vlad has found a magic box. If he opens it now he will only get $15. But every month the amount in the box increases by $15. If

Triss [41]

He would have to wait 30 months to get $450

4 0

3 years ago

There are five tests in a grading period. A student received grades of 98, 80, and 90, 96 on the first four tests. What grade mu

inn [45]

Answer:

80

Step-by-step explanation:

The median of the group is 80

If you add all the five numbers up they equal 454 divide by 5 the answer would be 90.8

3 0

4 years ago

Please help me with this math question!

barxatty [35]

1) Change radical forms to fractional exponents using the rule:
The n<span>th root of "</span>a number" = "that number" raised to the<span> reciprocal of n.
For example </span> $\sqrt[n]{3} = 3^{ \frac{1}{n} }$ .

The square root of 3 ( $\sqrt{3}$ ) = 3 to the one-half power ( $3^{ \frac{1}{2} }$ ).
The 5th root of 3 ( $\sqrt[5]{3}$ ) = 3 to the one-fifth power ( $3^{ \frac{1}{5} }$ ).

2) Now use the product of powers exponent rule to simplify:
This rule says $a^{m} a^{n} = a^{m+n}
$ . When two expressions with the same base (a, in this example) are multiplied, you can add their exponents while keeping the same base.

You now have $(3^{ \frac{1}{2} })*(3^{ \frac{1}{5} })$ . These two expressions have the same base, 3. That means you can add their exponents:
$(3^{ \frac{1}{2} })(3^{ \frac{1}{5} })\\
= 3^{(\frac{1}{2} + \frac{1}{5}) }\\
= 3^{\frac{7}{10}}$

3) You can leave it in the form $3^{\frac{7}{10}}$ or change it back into a radical $\sqrt[10]{3^7}$

------

Answer: $3^{\frac{7}{10}}$ or $\sqrt[10]{3^7}$

6 0

4 years ago

A TV station claims that 38% of the 6:00 - 7:00 pm viewing audience watches its evening news program. A consumer group believes

Elena L [17]

Answer:

$z=\frac{0.340 -0.38}{\sqrt{\frac{0.38(1-0.38)}{830}}}=-2.374$

$p_v =P(Z$

So the p value obtained was a very low value and using the significance level given $\alpha=0.05$ we have $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can said that at 5% of significance the proportion of people that regularly watch the TV station’s news program is significantly less than 0.38 .

Step-by-step explanation:

1) Data given and notation

n=830 represent the random sample taken

X=282 represent the people that regularly watch the TV station’s news program

$\hat p=\frac{282}{830}=0.340$ estimated proportion of people that regularly watch the TV station’s news program

$p_o=0.38$ is the value that we want to test

$\alpha=0.05$ represent the significance level

Confidence=95% or 0.95

z would represent the statistic (variable of interest)

$p_v$ represent the p value (variable of interest)

2) Concepts and formulas to use

We need to conduct a hypothesis in order to test the claim that the proportion is less than 0.38:

Null hypothesis: $p\geq 0.38$

Alternative hypothesis: $p < 0.38$

When we conduct a proportion test we need to use the z statisitc, and the is given by:

$z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}$ (1)

The One-Sample Proportion Test is used to assess whether a population proportion $\hat p$ is significantly different from a hypothesized value $p_o$ .

3) Calculate the statistic

Since we have all the info requires we can replace in formula (1) like this:

$z=\frac{0.340 -0.38}{\sqrt{\frac{0.38(1-0.38)}{830}}}=-2.374$

4) Statistical decision

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.

The significance level provided $\alpha=0.05$ . The next step would be calculate the p value for this test.

Since is a left tailed test the p value would be:

$p_v =P(Z$

So the p value obtained was a very low value and using the significance level given $\alpha=0.05$ we have $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can said that at 5% of significance the proportion of people that regularly watch the TV station’s news program is significantly less than 0.38 .

3 0

3 years ago