A sample of a radioactive isotope had an initial mass of 550 mg in the year 2009 and decays exponentially over time. A measurement in the year 2015 found that the sample's mass had decayed to 90 mg. What would be the expected mass of the sample in the year 2020, to the nearest whole number?

Aresearch company wants to test the claim that a new multivitamin to improve short term memory. state the objective of the experiment, suggest a population, determine the experimental and control groups, and describe a sample procedure.

Identify the converse of the following conditional: if a point is in the first quadrant, then its coordinates are positive. if the coordinates of a point are not positive, then the point is not in the first quadrant. if the coordinates of a point are positive, then the point is in the first quadrant. if a point is in the first quadrant, then its coordinates are positive. if a point is not in the first quadrant, then the coordinates of the point are not positive.

What is fraction that is equivalent to 3/8