At the beginning of an experiment, a scientist has 112 grams of radioactive goo. After 225 minutes, her sample has decayed to 14 grams.

What is the half-life of the goo in minutes?

Find a formula for , the amount of goo remaining at time.?

How many grams of goo will remain after 26 minutes?

Question

At the beginning of an experiment, a scientist has 112 grams of radioactive goo. After 225 minutes, her sample has decayed to 14 grams.

What is the half-life of the goo in minutes?

Find a formula for , the amount of goo remaining at time.?

How many grams of goo will remain after 26 minutes?

amistre64 · Answer

14 = 112e^(225r)

 14
---- = e^(225r)
112

ln(1/8) = 225r

r = ln(1/8)/225
...................................

y = 112e^(ln(1/8)/225)t lol

amistre64 · Answer

112/2 = 56


 56
---- = 1/2 ..... im getting dumber by the minute lol
112

ln(1/2)
------ = halftime 
  rate

amistre64 · Answer

half-life = 75 minutes

amistre64 · Answer

and im thinking 8' 2/3 after 26 minutes

amistre64 · Answer

but that last part is prolly wrong

amistre64 · Answer

http://www.wolframalpha.com/input/?i=112+e^%28%28ln%281%2F8%29%2F225%29x%29+at+x%3D26 thats better

anonymous · Answer

lol ur fine i thank you for trying and helping:)