there are more than 200 countries in the world
Set this up as
10 = 40 (1/2)t/28
and solve for t in years.
10/40 = (1/2)t/28
log(0.25) = (t/28) log(0.5)
t = 28 log(0.25) / log(0.5) years = 56 years
Test the answer:
56 years = 2(28 years) = 2 half-lives, so the remaining amount should be 1/2 of 1/2 of the initial amount, i.e. 1/4 of the initial amount, and 10 mg = 1/4 of 40 mg.
The answer is B. The citys tax base begins to increase because if it is redlines then they have to move somewhere else where it is harder to get money so they have to increase the taxes
Probability of an event happening=(numbers of ways it can happen) / (total numbers of outcomes)
P=probability that we are both selected
P₁=probability that I am selected and my brother is selected after.
P₂=probability that my brother is selected and I am selected afer.
P=P₁+P₂
P₁=(1/100)*(1/99)=1/9900
P₂=(1/100)*(1/99)=1/9900
P=1/9900 + 1/9900=2/9900≈0,0002≈0.02%
solution: P=2/9900≈0.02%
