SOLUTION: Osmium has a radioactive isotope that has a half life of 15.4 days. If one gram of the isotope is present now, then amount A (in grams) present after t days is A=(1/2)^t/15.4 H

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: Osmium has a radioactive isotope that has a half life of 15.4 days. If one gram of the isotope is present now, then amount A (in grams) present after t days is A=(1/2)^t/15.4 H      Log On


   



Question 87050: Osmium has a radioactive isotope that has a half life of 15.4 days. If one gram of the isotope is present now, then amount A (in grams) present after t days is A=(1/2)^t/15.4
How many days will pass before there is 0.73 grams of the isotope present? Round to the nearest day!
*So I thought to put the 0.73 in for A, and help would be fabulous! THANKS!

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
you're off to a good start ... .73=(.5)^(t/15.4) ... taking log of both sides gives log(.73)=(t/15.4)log(.5)

log(.73)/log(.5)=t/15.4 ... 15.4(log(.73)/log(.5))=t ... t approximately equals 7 days