A radioactive substance decays exponentially. A scientist begins with 140 milligrams of a radioactive substance. After 22 hours, 70 mg of the substance remains.

The number if marbles of different colors stored in a hat is listed below: 4 red marbles 10 green marbles 7 blue marbles. without looking in the hat, dan takes out a marble at random. he replaces the marble and then takes out another marble from the hat. what is the probability that dan takes out a blue marble in both draws?

Which of these tools or constructions is used to inscribe a hexagon inside a circle?

Which word in the sentence below is an interrogative pronoun? who is picking us up from school? whousisfrom