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3 years ago

What is the final concentration if a saline solution consisting of 20% NaCl is diluted using a 1/4 solution?

Mathematics

1 answer:

vodomira [7]3 years ago

6 0

Answer: C.V=C1.V1 +C2.V2

Step-by-step explanation: C=(C1V1 + C2V2)/V -> C=(20%.V+25%V)/2V-> C=22,5%

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Springfield and Futureland are 775 miles apart. Stephanie leaves Springfield traveling toward Futureland at 85 miles per hour. A

Genrish500 [490]

Answer:

425 miles

Step-by-step explanation:

Their speed of closure is the sum of their speeds: 85 + 70 = 155 miles per hour. Then they cover the 775 mile distance in

... (775 mi)/(155 mi/h) = 5 h

Stephanie has traveled (85 mi/h)·(5 h) = 425 mi from Springfield to their meeting point in that time.

8 0

3 years ago

kim just went to the store and bought 2 presents that cost kim $1,800 and her Taxes or 88 cents how much does kimmlin have to pa

strojnjashka [21]

3384 because .88 times 1800 is 1584 and you have to add that to 1800 making it 3384 (or the questions is really easy and its just 1800.88)

6 0

3 years ago

1/4 divided By 2 Show Your Work On How You Got The Answer

EastWind [94]

1/4 / 2 = 1/4*2 = 1/8

8 0

3 years ago

Help!!!

Artyom0805 [142]

Answer:

C: y+7=2/5(x+4)

Step-by-step explanation:

The point-slope form of the equation of a line with slope m through point (h, k) is ...

y -k = m(x -h)

You are given m=2/5 and (h, k) = (-4, -7). Put these numbers into the form and simplify the signs:

y -(-7) = 2/5(x -(-4)) . . . . . numbers put into the form

y +7 = 2/5(x +4) . . . . . . . signs simplified . . . . matches choice C

5 0

3 years ago

Rationalize the denominator of sqrt -49 over (7 - 2i) - (4 + 9i)

zubka84 [21]

$\sqrt{ \frac{-49}{(7-2i)-(4+9i) } } 
$

This one is quite the deal, but we can begin by distributing the negative on the denominator and getting rid of the parenthesis:

$\frac{ \sqrt{-49}}{7-2i-4-9i}$

See how the denominator now is more a simplification of like terms, with this I mean that you operate the numbers with an "i" together and the ones that do not have an "i" together as well. Namely, the 7 and the -4, the -2i with the -9i.
Therefore having the result:

$\frac{ \sqrt{-49} }{3-11i}$

Now, the $\sqrt{-49}$ must be respresented as an imaginary number, and using the multiplication of radicals, we can simplify it to $\sqrt{49} \sqrt{-1}$
This means that we get the result 7i for the numerator.

$\frac{7i}{3-11i}$

In order to rationalize this fraction even further, we have to remember an identity from the previous algebra classes, namely: $x^2 - y^2 =(x+y)(x-y)$
The difference of squares allows us to remove the imaginary part of this fraction, leaving us with a real number, hopefully, on the denominator.

$\frac{7i (3+11i)}{(3-11i)(3+11i)}$

See, all I did there was multiply both numerator and denominator with (3+11i) so I could complete the difference of squares.
See how $(3-11i)(3+11i)= 3^2 -(11i)^2$ therefore, we can finally write:

$\frac{7i(3+11i)}{3^2 - (11i)^2 }$

I'll let you take it from here, all you have to do is simplify it further.
The simplification is quite straightforward, the numerator distributed the 7i. Namely the product $7i(3+11i) = 21i+77i^2$ .
You should know from your classes that i^2 = -1, thefore the numerator simplifies to $-77+21i$
You can do it as a curious thing, but simplifying yields the result:
$\frac{-77+21i}{130}$

7 0

3 years ago