Question 1090745
A 300g sample of thorium-234 has a half-life of 24 days.
 The mass of thorium, in grams, that remains after t days can be modeled by:
 M(t)=300(1/2)^t/24.
 what mass will remain after 31 days? 
:
{{{M(t) = 300(.5)^(31/24)}}}; the exponent is {{{31/24}}} 
Use your calc
M(t) = 300*.408479
M(t) = 122.54 grams remain after 31 days