Solve a “Half-Life” Equation for a Specific Number of Years

[PanickyPapaya]

This is my first post so I’m not super sure if I’m doing this right but here it goes... This is a question from a Case Study assignment I’m working on. I’ve been stuck on it for like an hour now. I had it all worked out, but my answer didn’t match any of the answer choices. So, I know I messed up somewhere, but I can’t figure out what I did wrong. This is my (incorrect) work:

 

[Deleted member 4993]

View attachment 13464

This is my first post so I’m not super sure if I’m doing this right but here it goes... This is a question from a Case Study assignment I’m working on. I’ve been stuck on it for like an hour now. I had it all worked out, but my answer didn’t match any of the answer choices. So, I know I messed up somewhere, but I can’t figure out what I did wrong. This is my (incorrect) work:

View attachment 13465

What are the choices given to you?

 

[PanickyPapaya]

What are the choices given to you?

21,771,120 years, 29,762,960 years, and 37,150850 years

 

[Deleted member 4993]

View attachment 13464

This is my first post so I’m not super sure if I’m doing this right but here it goes... This is a question from a Case Study assignment I’m working on. I’ve been stuck on it for like an hour now. I had it all worked out, but my answer didn’t match any of the answer choices. So, I know I messed up somewhere, but I can’t figure out what I did wrong. This is my (incorrect) work:

View attachment 13465

You made a mistake while multiplying 2.322 by 16*10^6. the correct answer is 37.151 * 10^6 years.

 

[Dr.Peterson]

It also looks like they didn't round the log as you did; keep all the digits in your calculator from one step to the next (and at the end, round to the nearest year).

On the other hand, the half-life can't really be that exact; using significant digits, the answer should be 37 million years.