Element X decays radioactively with a half life of 9 minutes. If there are 550 grams of Element X, how long, to the nearest tenth of a minute, would it take the element to decay to 13 grams?

Fred has a spinner that is split into four equal sections: red, blue, green, and yellow. fred spun the spinner 688 times. which of the following would be a good estimate of the number of times the spinner lands on the green section? a. 269 b. 603 c. 344 d. 189