Question 1030630
P=po*exp(-kt)
p= 1/2 po, because it is half as much
therefore, 1/2=exp(-kt)
ln both sides
ln(1/2)=-8.3k
0.693/8.3=k
do without rounding until end
0.0835=k
Here, you want (1/15) to be the ratio.
t is not known, but k is
therefore, (1/15)=exp(-0.0835*t)
ln both sides
t=32.43 days