Question

question 7 (3 points)
you receive an order for 125 ml of 4% acetic acid solution, and you have in stock 75% acetic acid solution.
how many ml of the 75% solution will you need? (you must round to the nearest tenths.)

Explanation:

Step1: Set up the equation

Let \( x \) be the volume (in mL) of the 75% acetic acid solution needed. The amount of acetic acid in the 75% solution is \( 0.75x \), and the amount of acetic acid in the final 125 mL of 4% solution is \( 0.04 \times 125 \). Since the amount of acetic acid before and after dilution remains the same, we have the equation:
\( 0.75x = 0.04 \times 125 \)

Step2: Solve for \( x \)

First, calculate the right - hand side of the equation: \( 0.04\times125 = 5 \)
Then, solve for \( x \) by dividing both sides of the equation \( 0.75x = 5 \) by 0.75:
\( x=\frac{5}{0.75}=\frac{5\times4}{0.75\times4}=\frac{20}{3}\approx6.7 \) (rounded to the nearest tenths)

Answer:

\( 6.7 \)