Hello, i no longer need help with this problem thank you

natka813 [3]

Answer:

40

Step-by-step explanation:

In word problems, the word "of" usually means multiply. Thus, for example, 10% of $50 is $5. This is because we can write 10% as 0.10 or as 10/100 (which is 1/10) and then multiply: (1/10)(50) = 5

So, we often see equations like:

R = (1/2)D meaning R is 50% of D, or R is half of D

Let x = the number we want to find

This problem says:

"12 is 30% of what number?"

12 = (30/100) * x

12 = (3/10)x

(10/3)12 = x [multiply both sides by (10/3)]

40 = x

Checking (very important):

Is 12 = (3/10)(40) ?

12 = (3)(4) ?

12 = 12 ? yes

7 0

2 years ago

Read 2 more answers

What is the volume, in cubic cm, of a rectangular prism with a height of 10cm, a width of 20cm, and a length of 11cm??

Alex787 [66]

here's the solution,

=》volume = l × b × h

where,

l = lenght
b = width
h = height

so,

=》

$v = 11 \times 20 \times 10$

=》

$2200$

so, volume = 2200 cm³

7 0

3 years ago

15.7·3.09+15.7·2.91 Please help. WILL GIVE BRAINLIEST!

frez [133]

Answer:

the answer is 94.2

Step-by-step explanation:

5 0

3 years ago

Measurements of the sodium content in samples of two brands of chocolate bar yield the following results (in grams):

Tpy6a [65]

Answer:

98% confidence interval for the difference μX−μY = [ 0.697 , 7.303 ] .

Step-by-step explanation:

We are give the data of Measurements of the sodium content in samples of two brands of chocolate bar (in grams) below;

Brand A : 34.36, 31.26, 37.36, 28.52, 33.14, 32.74, 34.34, 34.33, 29.95

Brand B : 41.08, 38.22, 39.59, 38.82, 36.24, 37.73, 35.03, 39.22, 34.13, 34.33, 34.98, 29.64, 40.60

Also, $\mu_X$ represent the population mean for Brand B and let $\mu_Y$ represent the population mean for Brand A.

Since, we know nothing about the population standard deviation so the pivotal quantity used here for finding confidence interval is;

P.Q. = $\frac{(Xbar -Ybar) -(\mu_X-\mu_Y)}{s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2} } }$ ~ $t_n__1+n_2-2$

where, $Xbar$ = Sample mean for Brand B data = 36.9

$Ybar$ = Sample mean for Brand A data = 32.9

$n_1$ = Sample size for Brand B data = 13

$n_2$ = Sample size for Brand A data = 9

$s_p = \sqrt{\frac{(n_1-1)s_X^{2}+(n_2-1)s_Y^{2} }{n_1+n_2-2} }$ = $\sqrt{\frac{(13-1)*10.4+(9-1)*7.1 }{13+9-2} }$ = 3.013

Here, $s^{2}_X$ and $s^{2} _Y$ are sample variance of Brand B and Brand A data respectively.

So, 98% confidence interval for the difference μX−μY is given by;

P(-2.528 < $t_2_0$ < 2.528) = 0.98

P(-2.528 < $\frac{(Xbar -Ybar) -(\mu_X-\mu_Y)}{s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2} } }$ < 2.528) = 0.98

P(-2.528 * $s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2}$ < $(Xbar -Ybar) -(\mu_X-\mu_Y)$ < 2.528 * $s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2}$ ) = 0.98

P( (Xbar - Ybar) - 2.528 * $s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2}$ < $(\mu_X-\mu_Y)$ < (Xbar - Ybar) + 2.528 * $s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2}$ ) = 0.98

98% Confidence interval for μX−μY =

[ (Xbar - Ybar) - 2.528 * $s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2}$ , (Xbar - Ybar) + 2.528 * $s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2}$ ]

[ $(36.9 - 32.9)-2.528*3.013\sqrt{\frac{1}{13} +\frac{1}{9}$ , $(36.9 - 32.9)+2.528*3.013\sqrt{\frac{1}{13} +\frac{1}{9}$ ]

[ 0.697 , 7.303 ]

Therefore, 98% confidence interval for the difference μX−μY is [ 0.697 , 7.303 ] .

4 0

3 years ago

If you divide one of the roots of the equation 4x2+bx−27=0 by the other root, the quotient will be −3. Find b.

klio [65]

<h3>Answer:</h3>

±12 (two answers)

<h3>Explanation:</h3>

Suppose one root is <em>a</em>. Then the other root will be -3<em>a</em>. The product of the two roots is the ratio of the constant coefficient to the leading coefficient:

(<em>a</em>)(-3<em>a</em>) = -27/4

<em>a</em>² = -27/(4·(-3)) = 9/4

<em>a</em> = ±√(9/4) = ±3/2

Then the other root is

-3<em>a</em> = -3(±3/2) = ±9/2 . . . . . . the roots will have opposite signs

We know the opposite of the sum of these roots will be the ratio of the linear term coefficient to the leading coefficient: b/4, so ...

-(a + (-3a)) = b/4

2a = b/4

b = 8a = 8·(±3/2)

b = ±12

_____

<em>Check</em>

For b = 12, the equation factors as ...

4x² +12x -27 = (2x -3)(2x +9) = 0

It has roots -9/2 and +3/2, the ratio of which is -3.

For b = -12, the equation factors as ...

4x² -12x -27 = (2x +3)(2x -9) = 0

It has roots 9/2 and -3/2, the ratio of which is -3.

4 0

3 years ago