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3 years ago

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Kristina wants to buy a flute that costs 240 . She has saved 20 each week for 3 weeks . How many more weeks does Kristina need t

o save money if she continues to save 20 each week

1 answer:

Burka [1]3 years ago

7 0

Answer:

9 more weeks

Explanation:

She already saved 20(3)=60

240=60+20(x)
X=9
She needs 9 more weeks

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You have been doing research for your statistics class on the prevalence of severe binge drinking among teens. You have decided

Serggg [28]

Answer:

(1.218 ; 1.322)

the confidence interval is appropriate

Step-by-step explanation:

The confidence interval :

Mean ± margin of error

Sample mean = 1.27

Sample standard deviation, s = 0.80

Sample size, n = 914

Since we are using tbe sample standard deviation, we use the T table ;

Margin of Error = Tcritical * s/√n

Tcritical at 95% ; df = 914 - 1 = 913

Tcritical(0.05, 913) = 1.96

Margin of Error = 1.96 * 0.80/√914 = 0.05186

Mean ± margin of error

1.27 ± 0.05186

Lower boundary = 1.27 - 0.05186 = 1.218

Upper boundary = 1.27 + 0.05186 = 1.322

(1.218 ; 1.322)

According to the central limit theorem, sample means will approach a normal distribution as the sample size increases. Hence, the confidence interval is valid, the sample size of 914 gave a critical value at 0.05 which is only marginally different from that will obtained using a normal distribution table. Hence, the confidence interval is appropriate

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3 years ago

How is the graph of y=3(x+1)^2 related to its parent function y=x^2

creativ13 [48]

The parent function is y = x^2

There is a compression of 3:

y = 3x^2

There is a shift by 1 unit to the left:

y = 3(x + 1)^2

3 0

2 years ago

Read 2 more answers

8w-15=57 two step equations

insens350 [35]

Answer:

w=9

Step-by-step explanation:

Our equation is: 8w-15=57

Add 15 to both sides

-15 is now gone because we added 15 so it would be zero

and we have 72 because 15 plus 57 is 72

Now we have:

8w=72

Divide by 8 on both sides

8w cancels out to just w

and 72 divided by 8 is 9

And you're left with:

w=9

7 0

3 years ago

At what point on the parabola y = 3x^2 + 2x is the tangent line parallel to the line<br> y = 10x −2?

oksian1 [2.3K]

Answer:

( $\frac{4}{3}$ , 8 )

Step-by-step explanation:

the equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

y = 10x - 2 ← is in slope- intercept form

with slope m = 10

Parallel lines have equal slopes

then the tangent to the parabola with a slope of 10 is required.

the slope of the tangent at any point on the parabola is $\frac{dy}{dx}$

differentiate each term using the power rule

$\frac{d}{dx}$ (a $x^{n}$ ) = na $x^{n-1}$ , then

$\frac{dy}{dx}$ = 6x + 2

equating this to 10 gives

6x + 2 = 10 ( subtract 2 from both sides )

6x = 8 ( divide both sides by 6 )

x = $\frac{8}{6}$ = $\frac{4}{3}$

substitute this value into the equation of the parabola for corresponding y- coordinate.

y = 3( $\frac{4}{3}$ )² + 2

= (3 × $\frac{16}{9}$ ) + 2

= $\frac{16}{3}$ + $\frac{8}{3}$

= $\frac{24}{3}$

= 8

the point on the parabola with tangent parallel to y = 10x - 2 is ( $\frac{4}{3}$ , 8 )

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1 year ago

Ms.harper estimates that 125 students will attend the school dance. There was an actual total of 148 who attended the dance. Fin

Vladimir [108]

Answer:

The answer would be 118.4%

Step-by-step explanation:

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2 years ago