ANSWER
1: 1/2
2: 4/9
3: 8
4: 5/18
5: Theo= What should happen
Exp= What actually happens
A half-life of 9 minutes corresponds to a decay factor <em>k</em> such that

Then the time it takes for the substance to decay from 610 g to 124 g is time <em>t </em>such that

Solve for <em>t</em> :



so it takes about 20.7 min for the 610 g sample to decay down to 124 g.
The answer is x*2 equals negative 2
The answer is D 105 because i know