Question

Amy has 1% solution and 7% solution. How much must she mix to have 210 L of 3% of solution?

A. Mix 100 L of the 1% solution and 110 L of the 7% solution.
B. Mix 140 L of the 1% solution and 70 L of the 7% solution.
C. Mix 70 L of the 1% solution and 140 L of the 7% solution.
D. Mix 110 L of the 1% solution and 100 L of the 7% solution.

Answer 1

To find out how much of each solution Amy needs to mix to get 210 L of a 3% solution, we can set up a system of equations. The correct answer is mix 140 L of the 1% solution and 70 L of the 7% solution.

Step-by-step explanation:

To find out how much of each solution Amy needs to mix to get 210 L of a 3% solution, we can set up a system of equations.

Let x represent the amount of the 1% solution and y represent the amount of the 7% solution. Since she needs a total of 210 L of the final solution, we have the equation:

x + y = 210

Since a 1% solution has 1% of solute and a 7% solution has 7% of solute, we can set up another equation based on the solute in the final solution:

0.01x + 0.07y = 0.03(210)

Simplifying the second equation, we get:

0.01x + 0.07y = 6.3

Using the method of substitution or elimination, we can solve this system of equations to find the values of x and y. The correct answer is option B: Mix 140 L of the 1% solution and 70 L of the 7% solution.