A radioactive material has a half-life of 1.0 hour If 200.0 g of it was present at 6 a.m. on a certain day, how many grams will have decayed by 9 a.m. on the same day?
175.0 g
150.0 g
100.0 g
187.5 g
Correct answer is A
No explanation has been provided for this answer.