Answer:
The number of tigers decays by a factor of
every 0.50 years
Step-by-step explanation:
The correctly written function is

Convert 16/25 into its equivalent form (4/5)²

If you make t = 1/2, this is half-year, the population of tigers will decay by a factor of 4/5 in that time. Every time the half-year passes, the population is multiplied by 4/5, which means that the polulation will decay by a factor of 4/5 whenever half a year elapses.
Hence, the number of tigers decays by a factor of 4/5 every 0.50 years.