Khan sucks 3 for 30 points again

Mathematics

1 answer:

tester [92]2 years ago

7 0

Answer:

D, John did not make a mistake!

Step-by-step explanation:

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Plz Help???

GREYUIT [131]

1.
12 liters of 26% acid solution contain $26\% \times 12=0.26 \times 12=3.12$ liters of acid.
x liters of 40% acid solution contain $40\%x=0.4x$ liters of acid.
The third solution is made from the two mixed solution so its volume is $12+x$ , and the volume of acid in it is $0.4x+3.12$ . Its concentration is 33% or 0.33.
The concentration of a solution is the volume of the solution divide by the volume of acid in it.

$\frac{0.4x+3.12}{12+x}=0.33 \\ 0.4x+3.12=0.33(12+x) \\ 0.4x+3.12=3.96+0.33x \\
0.07x=0.84 \\
x=12$

The answer is B.

2.
12 liters of 16% acid solution contain $16\% \times 12=0.16 \times 12=1.92$ liters of acid.
x liters of 40% acid solution contain $40\%x=0.4x$ liters of acid.
The volume of the third solution is $12+x$ , and the volume of acid in it is $0.4x+1.92$ . Its concentration is 32% or 0.32.

$\frac{0.4x+1.92}{12+x}=0.32 \\
0.4x+1.92=0.32(12+x) \\
0.4x+1.92=3.84+0.32x \\
0.08x=1.92 \\
x=24$

The answer is B.

3.
16 liters of 18% acidsolution contain $18\% \times 16=0.18 \times 16=2.88$ liters of acid.
x liters of 27% acid solution contain $27\%x=0.27x$ liters of acid.
The volume of the third solution is $16+x$ , and the volume of acid in it is $0.27x+2.88$ . Its concentration is 21% or 0.21.

$\frac{0.27x+2.88}{16+x}=0.21 \\
0.27x+2.88=0.21(16+x) \\
0.27x+2.88=3.36+0.21x \\
0.06x=0.48 \\
x=8$

The answer is A.

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3 years ago

Write 6.74 * 10^9 in standard notation.

kaheart [24]

That would be 6,740,000,000

7 0

2 years ago

Read 2 more answers

Find in the missing values to make the equations true.

Vikki [24]

Answer: 21

Log8(8 is under the log) the answer is 7