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never [62]
3 years ago
5

How many ml of 20 percent acid should be added to pure acid to make 70 ml of 30 percent acid?

Mathematics
1 answer:
Novay_Z [31]3 years ago
8 0

Answer:

61.25%

Step-by-step explanation:

How many ml of 20 percent acid should be added to pure acid

to make 70 ml of 30 percent acid?

:

let x = amt of 20% mixture

then

(70-x) = amt of pure acid

:

0.20x + (70-x) =0 .30(70)

0.20x + 70 - x = 21

= 21 - 70

-0.8x =-49

x = 61.25%

x = +61.25 ml of 20% stuff

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Simplify the expression.<br><br><br> Write your answer without negative exponents.
Phoenix [80]

Answer:

-5/ (x^19 * y^12)

Step-by-step explanation:

-15x^-10 * y ^ -3 * x^-9 * y^-9/3 (It's writing it like this.)

15 and 3 have a GCF of 3.

-5x^-10 * y^-3 * x^-9 * y^-9/1

Reduce similar occurrences. *twice in a row*

-5x^(-10 + (-9)) * y^(-3 + (-9))/1

Remove extra signs *twice in a row*

-5x^(-10 - 9) * y^(-3 - 9)/1

Remove extraneous 1.

-5x^(-10 - 9) * y^(-3 - 9)

Add integers.

-5x^-19 * y^-12

Negative powers change multiplication to division.

-5 / (x^19 * y^12) is the final answer.

Even with that, the simplified answer wouldn't have negative exponents because of the negative powers rule.

8 0
2 years ago
3/4x=-18 what is the answer?
Afina-wow [57]

Answer:

X= 24

Step-by-step explanation:

Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation :

                    3/4*x-(18)=0

Step by step solution :

Step  1  :

           3

Simplify   —

           4

Equation at the end of step  1  :

  3        

 (— • x) -  18  = 0

  4        

Step  2  :

Rewriting the whole as an Equivalent Fraction :

2.1   Subtracting a whole from a fraction

Rewrite the whole as a fraction using  4  as the denominator :

         18     18 • 4

   18 =  ——  =  ——————

         1        4  

Equivalent fraction : The fraction thus generated looks different but has the same value as the whole

Common denominator : The equivalent fraction and the other fraction involved in the calculation share the same denominator

Adding fractions that have a common denominator :

2.2       Adding up the two equivalent fractions

Add the two equivalent fractions which now have a common denominator

Combine the numerators together, put the sum or difference over the common denominator then reduce to lowest terms if possible:

3x - (18 • 4)     3x - 72

—————————————  =  ———————

      4              4  

Step  3  :

Pulling out like terms :

3.1     Pull out like factors :

  3x - 72  =   3 • (x - 24)

Equation at the end of step  3  :

 3 • (x - 24)

 ————————————  = 0

      4      

Step  4  :

When a fraction equals zero :

4.1    When a fraction equals zero ...

Where a fraction equals zero, its numerator, the part which is above the fraction line, must equal zero.

Now,to get rid of the denominator, Tiger multiplys both sides of the equation by the denominator.

Here's how:

 3•(x-24)

 ———————— • 4 = 0 • 4

    4    

Now, on the left hand side, the  4  cancels out the denominator, while, on the right hand side, zero times anything is still zero.

The equation now takes the shape :

  3  •  (x-24)  = 0

Equations which are never true :

4.2      Solve :    3   =  0

This equation has no solution.

A a non-zero constant never equals zero.

Solving a Single Variable Equation :

4.3      Solve  :    x-24 = 0

Add  24  to both sides of the equation :

                     x = 24

One solution was found :

                  x = 24

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3 years ago
Why do I think I'm ugly
Tanya [424]

Answer:

Ok listen here

Step-by-step explanation:

You are like the earth.

On the inside is a bright center and lava. When lava comes to the surface as a volcano, many people think it's ugly and dangerous, but other people think that it's beautiful.

We all know that a lot of people think the surface of the earth is ugly, and they have given up hope that people can change it, but the truth is that, the world is beautiful and we can change it.

You are beautiful and the people on your earth are represented as your brain. Your brain needs to tell you to look at yourself and to say that you are beautiful. You can change your mindset to tell you that you don't care what other people say, all that matters is what you say.

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A crayon has a mass of 30 grams. How many crayons can be made with 30 kilograms of colored wax
PolarNik [594]
The conversion factor between kilo and base unit which is grams in this question is 1000 so there is 1000 grams in 1 kilogram so first we need to convert kilograms to grams so we multiply by 1000 so 30kgx1000= 30000 grams so to find the number of crayons then we divide by 30 which is the mass of one crayon to find out how many we need so 30000/30= 1000 so you would need 1000 crayons
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3 years ago
I need help with question 30 please! :)
Nataliya [291]

Answer:

B ∩ (A ∪ C)'

Step-by-step explanation:

It's the B part excluding A and C union. Hence,

(A ∪ C)' ∩ B

7 0
2 years ago
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