Question

A scientist has two solutions, which she has labeled Solution A and Solution B. Each contains salt. She knows that Solution A is 65% salt and Solution B is 80% salt. She wants to obtain 120 ounces of a mixture that is 70% salt. How many ounces of each solution should she use?

Answer 1

We can use these variables:

A = number of ounces for solution A
B = Number of ounces for solution B

A + B = 20

Now, we can use decimal conversions.

0.65A + 0.80B = 0.70(120)

Next step: We substitute A into 120 - B to show their relationship.

0.65(120 - B) + 0.80B = 84

Now onto the next equation:

78 - 0.65B + 0.80B = 84
0.80 - 0.65 = 0.15, so…

0.15B = 84 - 78
0.15B = 6
B = 6 divided by 0.15
B = 40 ounces

To find A, we can simply plug B into the starting equation.

A = 120 - 40
A = 60 ounces

Your final answer: The scientist should use 60 ounces of solution A and she should use 40 ounces of solution B. Yeah