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Morgarella [4.7K]

3 years ago

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scientist needs 120 liters of a 20% acid solution for an experiment. The lab has available a 25% and a 10% solution. How many li

ters of the 25% and how many liters of the 10% solutions should the scientist mix to make the 20% solution?

1 answer:

sattari [20]3 years ago

4 0

Answer:

The scientist needs 80 liters of 25% solution and 40 liters of 10% solution.

Step-by-step explanation:

If x is the liters of 25% solution, and y is the liters of 10% solution, then:

x + y = 120

0.25x + 0.10y = 0.20(120)

Solve the system of equations using substitution or elimination. Using substitution:

0.25x + 0.10(120 − x) = 0.20(120)

0.25x + 12 − 0.10x = 24

0.15x = 12

x = 80

y = 40

The scientist needs 80 liters of 25% solution and 40 liters of 10% solution.

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Nonamiya [84]

Combine the terms by multiplying into a single fraction.

$\bf{\dfrac{5}{2}x-7=\dfrac{3}{4}x+14 }$

Find the common denominator.

$\bf{\dfrac{5x}{2}-7=\dfrac{3}{4}x+14 }$

Combine fractions with the lowest common denominator.

$\bf{\dfrac{5x(-7)}{2}=\dfrac{3}{4}x+14 }$

Multiply the numbers.

$\bf{\dfrac{5x-14}{2}=\dfrac{3}{4}x+14 }$

Combine the multiplied terms into a single fraction

$\bf{\dfrac{5x-14}{2}=\dfrac{3x}{4}+14 }$

Find the common denominator.

$\bf{\dfrac{5x-14}{2}=\dfrac{3x}{4}+\dfrac{4\cdot14}{4} }$

Combine fractions with the lowest common denominator.

$\bf{\dfrac{5x-14}{2}=\dfrac{3x+4\cdot14}{4} }$

Multiply the numbers.

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Eliminate the denominators of the fractions.

$\bf{4\cdot\dfrac{5x-14}{2}=4\cdot\dfrac{3x+56}{4} }$

Cancel the multiplied terms that are in the denominator.

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To distribute.

$\bf{10x-28=3x+56 }$

Add 28 to both sides.

$\bf{10x-28+28=3x+56+28 }$

Simplify

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Simplify

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Divide both sides by the same factor.

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Simplify

$\bf{x=12 \ \ \ === > \ \ \ Answer}$

↓

<h3>Verification</h3>

Let x=12.

$\bf{\dfrac{5}{2}\times12-7=\dfrac{3}{4}\times12+14 }$
$\bf{\dfrac{5\times12}{2}-7=\dfrac{3}{4}\times12+14 }$
$\bf{\dfrac{60}{2}-7=\dfrac{3}{4}\times12+14 }$
$\bf{30-7=\dfrac{3}{4}\times12+14 }$
$\bf{30-7=\dfrac{3\times12}{4}+14 }$
$\bf{30-7=\dfrac{36}{4}+14 }$
$\bf{30-7=9+14 }$
$\bf{23=9+14 }$
$\bf{23=23}$

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