Answer:
50 liters
Step-by-step explanation:
If x is the volume of 20% acid, then:
x (0.20) + 20 (0.45) = (x + 20) (0.30)
0.2x + 9 = 0.3x + 6
3 = 0.1x
x = 30
30 liters of 20% acid are needed, so there will be a total of 50 liters of 30% acid.
<u>Answer:</u>
37 minutes
<u>Step-by-step explanation:</u>
Lena has 20 dollars. 20 - 12.23 = 7.77
Lena has $7.77 dollars left.
We divide this by .21 to see how many minutes her call was.
7.77 ÷ .21 = 37
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The aswer would be B because you have to divide a couple numbers to get 20in.
The answer would be B, due to the fact that the shaded area is above the line.
Answer:
or 
Step-by-step explanation:
we know that
Applying the law of cosines

In this problem we have

c is the length of the third side
Substitute




or 