How do I find out the answer to this story problem?a city of 2,950,000 people has a 2.5% annual decrease in a population. What will the city's population be after 5yrs. 15yrs. and 25yrs.
Again, I disagree with raely's approach. I think you need to calculate the 2.5% based on each year's declining population.
After one year
2,950,000 x .025 = 73,750 decrease
So, the population after one year is
2,950,000 - 73,750 = 2,876,250
After two years
2,876,250 x .025 = 71,906 decrease
2,876,250 - 71,906 = 2,804,344 population
You can do the rest of the calculation. As a check, by my calculations the population after 5 years is 2,599,232.
5 yrs- 3,318,750
10 yrs- 3,687,500
15 yrs- 4,056,250
2,950,000 times .025 times the number of years= X +2,950,000. Take the number of people and multiply by the % annual increase and then the number of years and add the original number to get theamount for that year.