What is an expression that is equal to 3 x 2 1/4

What is 50% of $68? Show all of your work. Use the percent proportion model shown below to set up the equation before you calcul

Natali5045456 [20]

Answer:

$34

Step-by-step explanation:

50% is half of 100%

(Because 50% x 2 = 100%)

Thus, half the money ($68) to find 50%.

So, 68÷2 = 34

Final answer is $34

Or

50/100 x $68 =$34

Hope this helps!

6 0

2 years ago

Determine the value of a so that A = 2i+aj+k and B = 4i-2j-2k are perpendicular

Digiron [165]

In order to make them perpendicular, their dot product must result in zero. so:

$4 \times 2 - 2a - 2 \times 1 = 0$

$2a = 8 - 2 = 6$

$a = 3$

7 0

3 years ago

A Pew Internet poll asked cell phone owners about how they used their cell phones. One question asked whether or not during the

EastWind [94]

Answer:

a) $\hat p=\frac{471}{1024}=0.460$

The standard error is given by:

$SE= \sqrt{\frac{\hat p(1-\hat p)}{n}}=\sqrt{\frac{0.460(1-0.460)}{1024}}=0.0156$

And the margin of error is given by:

$ME=z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}=1.96\sqrt{\frac{0.460(1-0.460)}{1024}}=0.0305$

b) The 99% confidence interval would be given by (0.429;0.491)

Step-by-step explanation:

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 means 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.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{p(1-p)}{n}})$

Data given and notation

n=1024 represent the random sample taken

X=471 represent the people responded that they had used their cell phone while in a store within the last 30 days to call a friend or family member for advice about a purchase they were considering

$\hat p=\frac{471}{1024}=0.460$ estimated proportion of people responded that they had used their cell phone while in a store within the last 30 days to call a friend or family member for advice about a purchase they were considering

p= population proportion of people responded that they had used their cell phone while in a store within the last 30 days to call a friend or family member for advice about a purchase they were considering

Part a

The confidence interval would be given by this formula

$\hat p \pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}$

For the 95% confidence interval the value of $\alpha=1-0.95=0.05$ and $\alpha/2=0.025$ , with that value we can find the quantile required for the interval in the normal standard distribution.

$z_{\alpha/2}=1.96$

The standard error is given by:

$SE= \sqrt{\frac{\hat p(1-\hat p)}{n}}=\sqrt{\frac{0.460(1-0.460)}{1024}}=0.0156$

And the margin of error is given by:

$ME=z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}=1.96\sqrt{\frac{0.460(1-0.460)}{1024}}=0.0305$

Part b

If we replace the values obtained we got:

$0.460-1.96\sqrt{\frac{0.460(1-0.460)}{1024}}=0.429$

$0.460+1.96\sqrt{\frac{0.460(1-0.460)}{1024}}=0.491$

The 99% confidence interval would be given by (0.429;0.491)

8 0

3 years ago

What is the maximum number of relative extrema contained in the graph of this function f(x)=3x^3-x^2+4x-2

Sergeeva-Olga [200]

The maximum number of turning points in a cubic function is 2.

In this case,

$f(x)=3x^3-x^2+4x-2\implies f'(x)=9x^2-2x+4$

The discriminant is $(-2)^2-4(9)(4)=-140$ , which means the derivative has no real roots. This means there are no critical points and thus no turning points/relative extrema.

5 0

3 years ago

Read 2 more answers

F(x) = 4x^2 - 10.3 + 2 2<br> Find f(-7

Whitepunk [10]

Step-by-step explanation:

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7 0

2 years ago