Finding the Half Life From Activity

[Procrastinate]

I am meant to deduce the half life from this table (as attached.) I was under the impression that the half life would occur when the initial activity was halved but my answer of 2.34 minutes (from halving the initial activity of 36506) is wrong. Instead, the answer the textbook got was 1 minute. What did I do wrong?

 

[Kurdt]

Are you sure these things are related? How can the answer be in minutes when the timing was over hours?

 

[Procrastinate]

The answer was one minute and I got an 2.34 hours (my mistake.) I'm not sure what to do now...

 

[Dadface]

The answer of one minute does not match with this question.A quick glance at the table shows the answer is over two hours.