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alekssr [168]
3 years ago
7

Please help me. I really don't know what to do.

Mathematics
1 answer:
Natali [406]3 years ago
7 0
To me it is C. or D. but you would need a second opinion. Sorry.
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Theresa Morgan a chemist has a 10% hydrochloric acid solution and a 65% hydrochloric acid solution. How many liters of each shou
prisoha [69]

<u>ANSWER: </u>

170 liters of 10% hydrochloric acid must be mixed with 1700 liters of 65% hydrochloric acid solution to obtain 1870 liters of 60% solution.

<u>SOLUTION: </u>

First, set up a table. Fill in the unknowns with variables x and y. The table is attached below

From this, we can easily set up the two equations.  

Sum of values of two acids = Value of mixture  

0.1x + 0.65y = 1122  

For convenience, we'll multiply the entire equation by 100,

10x + 65y = 112200   ------ (1)  

Now, Sum of amounts of each acid = Amount of mixture  

x + y = 1870  ---------(2)

multiply (2) with 10 for easy calculation and derive the equation into one variable.

10x + 10y = 18700  

Subtracting equation (2) from (1),  

( + ) 10x + 65y = 112200

( − ) 10x + 10y = 18700

we get the solution as,

0 + 55y = 93500

Thus, 55y = 93500

y = 1700

Substituting y = 1700 in (2),

x + 1700 = 1870  

x  = 1870 - 1700  

x  = 170  

So, we have x = 170 and y = 1700

We can conclude that 170 liters of 10% hydrochloric acid must be mixed with 1700 liters of 65% hydrochloric acid solution  to obtain 1870 liters of 60% solution.

4 0
3 years ago
Which are the solutions of x² = 19x + 12​
Sever21 [200]

Answer:

\{x=\frac{19-\sqrt{409} }{2}\ , \  x=\frac{19+\sqrt{409} }{2}\}

Step-by-step explanation:

x² = 19x + 12

⇔ x² - 19x - 12 = 0

Calculating the discriminant :

b² - 4ac = (-19)² - 4×1×(-12) = 409

The discriminant is positive ,then the equation has two solutions.

x=\frac{19-\sqrt{409} }{2} \ \ or\ \ x=\frac{19+\sqrt{409} }{2}

4 0
2 years ago
10a-7b+11+8a-b-12 help pleas
mars1129 [50]
Combine like terms: 18a - 8b -1
7 0
2 years ago
Please help me with my math homework
Hatshy [7]

Answer:

So basically the mean is the average number.

Step-by-step explanation:

add all of them then divide by 6 (aka how many fractions)

8 0
3 years ago
Amanda and Stephen wrote the following proofs to prove that vertical angles are congruent. Who is correct? Line segment NT inter
alexira [117]
The answer:

the valid proof is <span>Amanda's.

</span><span>Statement Justification ∠1 + ∠4 = 180°
 Definition of Supplementary
Angles ∠3 + ∠4 = 180°
Definition of Supplementary Angles
∠1 + ∠4 = ∠3 + ∠4

Transitive Property of Equality ∠1 ≅ ∠3 </span>
5 0
3 years ago
Read 2 more answers
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