X = amount of the 18% solution
y = amount of the 40% solution
we know the 18% solution has only 18% of alcohol, the rest is maybe water or something, now, how many liters is 18%? well, 18% of anything is just (18/100) * anything, so, 18% of x is just (18/100) *x or 0.18x, and that's how many liters are there.
likewise, how many liters are there in the 40% solution? well, (40/100) * y, or 0.4y, that many.
we know the mixture has to yield 10 liters at 20% alcohol, how many liters of only alcohol is that? well, (20/100) * 10, or 2 liters.


how much of the 40% solution? well y = 10 - x
Answer:
y= -2x-22.
Step-by-step explanation:
1) the slope-interception common form is y=s*x+i, where 's' and 'i' are the slope and interception, unknown numbers;
2) if x₁= -3; y₁= -16, and s=-2, then the equation of the required line can be written in the point-interception form y-y₁=s(x-x₁); ⇔ y+16= -2(x+3);
3) the required equation in slope-interception form is:
y+16= -2x-6; ⇒ y= -2x-22.
note, the provided solution is not the only and shortest way.
Answer:
22.50
- 15.00
_______
7.50
Step-by-step explanation:
She still owes $7.50