SOLUTION: A scientist begins with 250 grams of a radioactive substance. After 250 minutes, the sample has decayed to 32 grams. Write an exponential equation f(t) representing this situation.
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Question 1129572: A scientist begins with 250 grams of a radioactive substance. After 250 minutes, the sample has decayed to 32 grams. Write an exponential equation f(t) representing this situation. (Let f be the amount of radioactive substance in grams and t be the time in minutes.)
To the nearest minute, what is the half-life of this substance?
You can put this solution on YOUR website! 32/250=0.128
A=Ao*2(-t/h)
32=250*2(-t/h)
0.128=2*(-250/h)
ln(0.128)=-250/h * ln2
divide both sides by ln2 and multiply by h
-2.9658h=-250
h=84.29 min or 84 min
0.128 is almost decayed 3 half lives, and 3 half lives would be 252 minutes, which is reasonable.
