Help Can’t decide whether it’s A or B

Initially 100 milligrams of a radioactive substance was present. after 6 hours the mass had decreased by 4%. if the rate of decay is proportional to the amount of the substance present at time t, find the amount remaining after 24 hours. (round your answer to one decimal place.)

Which is the solution to the inequality? 2 3/52 1/15 b< 3 2/15 b> 3 2/15

Can somebody 1. what is the formula for finding the vertical distance between two points on a coordinate plane?