With these questions?

mercury-197 has a half life of about 64 hours. after 288 hours about how many miligrams of a 750mg sample

643 mg
167 mg
33 mg
17mg

in 2010, a city population was 55,210 and it was declining at a rate of 1.09 each year. what is the best prediction for when the city population will first be below 48,000?
2019
2022
2025
2028

a population of 430,000 toads is expected to shrink at a rate of 5.5 per year. what is the best prediction for the toad population in 14 years?
236,500
194,766
59,125
13,821