Question 1133312
a.  y=20*0.5^(1/6)=17.8 microgm
b.  y=20*0.5^2=5.00 microgm
c. 1=20*0.5^(x/6)
0.05=0.5^(x/6)
ln both sides
ln 0.05=(x/6) ln 0.5
-3=(x/6)*(-0.693)
4.33=x/6
x=25.98 or 26.0 days