Let <em>x</em> and <em>y</em> be the required amounts of the 35% and 60% acid solutions, respectively.
<em>x</em> liters of 35% acid solution contains 0.35<em>x</em> L of acid.
<em>y</em> liters of 80% acid solution contains 0.80<em>y</em> L of acid.
Together, a combined (<em>x</em> + <em>y</em>) L of mixed solutions contains (0.35<em>x</em> + 0.80<em>y</em>) L of acid.
You want to end up with 60 L of 65% acid solution, which means
<em>x</em> + <em>y</em> = 60
0.35<em>x</em> + 0.80<em>y</em> = 0.65 × 60 = 39
Solve for <em>x</em> and <em>y</em> :
<em>y</em> = 60 - <em>x</em>
0.35<em>x</em> + 0.80 (60 - <em>x</em>) = 39
0.35<em>x</em> + 48 - 0.80<em>x</em> = 39
0.45<em>x</em> = 9
<em>x</em> = 20
<em>y</em> = 40
Using Pythagoras' theorem (a² + b² = c²), the correct answer is:
D. h² = a² - x²
Because a would be the hypotenuse, but h is not, so you have to rearrange the equation.
Answer:
100 minutes
Step-by-step explanation:
Let x = # of minutes
Company A: y = 21 + .17x
Company B: y = 26 + .12x
Set the equations = to each other.
21 + .17x = 26 + .12x
.17x = 5 + .12x
.05x = 5
x = 100