The answer is 65.9 because the place right after the decimal is the tenths place
how is the volume of a solution used in calculating concentration?
380 divide by 20
it will take her 19 hours to stamp 380 letters
8.9% is equal to 0.089 because a percent is over a 100. So, you can just multiply the ROI by the investment to get:

Your answer is:
$712.
The greatest common factor of two numbers, one of which is 1, will always be 1.