A chemist needs 80 milliliters of a 37% solution but has only 19% and 43% solutions available. Find how many milliliters of each that should be mixed to get the desired solution?

A chemist mixes a 10% saline solution with a 20% saline solution to make 500 milliliters of a 16% saline solution.

Step-by-step explanation:

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.