HS Calculus/math
posted by dt .
suppose that in any given year, the population of a certain endangered species is reduce by 25%. if the population is now 7500, in how many years will the population be 4000?

Solve this equation for n, the number of years:
4000 = 7500 * (0.75)^n
4000/7500 = 0.5333 = 0.75^n
n = (log 0.5333)/(log 0.75)
It will take a bit more than 2 years.
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