Use the approximate half-life formula for the case described below. Discuss whether the formula is valid for the case described. Poaching is causing a population of elephants to decline by 4% per year. What is the half-life for the population? If there are 10,000 elephants today, how many will remain in 50 years? Use the approximate half-life formula. What is the half-life for the population? years (Type an integer or decimal rounded to the nearest hundredth as needed.)