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jek_recluse [69]

3 years ago

9

How many gallons of a 20% acid solution should be mixed with 30 gallons of a 40% solution, to obtain a mixture of 30% acid solut

ion.

1 answer:

Alexeev081 [22]3 years ago

4 0

Answer:

30 gallons of 20% acid solution should be mixed.

Step-by-step explanation:

Let x gallons of a 20% acid solution was mixed with 30 gallons of a 40% solution, to obtain a mixture of 30% acid solution.

Therefore, final volume of the solution will be (x + 30) gallons.

Now concept to solve this question is

20%.(x) + 40%.(30) = 30%.(x + 30)

0.20(x) + 0.40(30) = 0.30(x + 30)

0.20x + 12 = 0.30x + 9

0.30x - 0.20x = 12 - 9

.10x = 3

x = $\frac{3}{0.1}$

x = 30 gallons

Therefore, 30 gallons of the 20% acid solution should be mixed.

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The half-life of a radioactive element is 130 days, but your sample will not be useful to you after 80% of the radioactive nu

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$ln|\frac mn|= ln|m|-ln|n|$
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$ln|e^a|=a$

$ln|a|=b \Rightarrow a=e^b$
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$\rightarrow -ln|2|=-\lambda \times 130$

$\rightarrow \lambda= \frac{-ln|2|}{-130}$

$\rightarrow \lambda= \frac{ln|2|}{130}$

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$N=\frac{80}{100}N_0$

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$\Rightarrow ln|{{\frac {80}{100}|=-\frac{ln2}{130}t$

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tankabanditka [31]

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