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3 years ago

14

If a scientist mixed 20% saline solution with 70% saline solution to get 10 gallons of 30% saline solution, how many gallons of

20% and 70% solutions were mixed?

1 answer:

Nana76 [90]3 years ago

4 0

60% yes 12344748498383

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Rewrite the expression by factoring out the coefficient of the variable.

mart [117]

Answer:

$- \frac{1}{2} x + 6$

by factorising out -½ :

${ \boxed{ \boxed{ = - \frac{1}{2} (x - 12)}}}$

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2 years ago

Solving systems by substitution: <br><br> Y=4x-17 <br> 4x+6y=10

sergey [27]

It's not a multiple choice answer is it?

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3 years ago

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Meg purchased a stereo system at a local store. It cost $675. She paid for it in six equal installments of $139 each. How much i

yawa3891 [41]

Answer:

159

Step-by-step explanation:

She paid 6 payments of 139

6*139 = 834

The cost was 675

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3 years ago

On a recent day 8 euros were worth $9 and 24 euros were worth $27 write an equation of the form y equals kx to show the relation

attashe74 [19]

Answer:

y=8x/9

Step-by-step explanation:

Given that 8 euros were worth $9 and

24 euros were worth $27.

Let y represent the number of Euros and x no of dollars.

Given that the relation is of the form y = kx+C

When x=0 y =0,

i.e. C =0

Hence equation is of the form y = kx

Substitute x=8 and y =9

We get 9 = 8k

Or k =8/9

Hence relation is y=8x/9 is the relation between x and y.

WE can verify this for 27 dollars worth 24 euros.

24 =8/9(27) is true.

Thus equation is verified.

6 0

3 years ago

Find the area of the surface. The part of the surface z = xy that lies within the cylinder x2 + y2 = 36.

rewona [7]

Answer:

Step-by-step explanation:

From the given information:

The domain D of integration in polar coordinates can be represented by:

D = {(r,θ)| 0 ≤ r ≤ 6, 0 ≤ θ ≤ 2π) &;

The partial derivates for z = xy can be expressed as:

$y =\dfrac{\partial z}{\partial x} , x = \dfrac{\partial z}{\partial y}$

Thus, the area of the surface is as follows:

$\iint_D \sqrt{(\dfrac{\partial z}{\partial x})^2+ (\dfrac{\partial z}{\partial y})^2 +1 }\ dA = \iint_D \sqrt{(y)^2+(x)^2+1 } \ dA$

$= \iint_D \sqrt{x^2 +y^2 +1 } \ dA$

$= \int^{2 \pi}_{0} \int^{6}_{0} \ r \sqrt{r^2 +1 } \ dr \ d \theta$

$=2 \pi \int^{6}_{0} \ r \sqrt{r^2 +1 } \ dr$

$= 2 \pi \begin {bmatrix} \dfrac{1}{3}(r^2 +1) ^{^\dfrac{3}{2}} \end {bmatrix}^6_0$

$= 2 \pi \times \dfrac{1}{3} \Bigg [ (37)^{3/2} - 1 \Bigg]$

$= \dfrac{2 \pi}{3} \Bigg [37 \sqrt{37} -1 \Bigg ]$

3 0

2 years ago