a population of 900 bears decreases by 15% per year. How many bears will there be in the population after 7 years? round to the nearest whole number
289
2394
9
795
would it be 289?
100 - 15 = 85% left after each year
900 * 0.85^7 = 900 * 0.320577088
= 289 approximately
Oh, bear with me while I calculate this for you!
If the population of bears decreases by 15% each year, then the population after 7 years would be approximately 289 bears. Good job, you're not just "grizzly" guessing!
To find the number of bears after 7 years, you need to calculate the population after each year.
Year 1: 900 - (15% of 900) = 900 - (0.15 * 900) = 900 - 135 = 765 bears
Year 2: 765 - (15% of 765) = 765 - (0.15 * 765) = 765 - 114.75 ≈ 650 bears
Year 3: 650 - (15% of 650) = 650 - (0.15 * 650) = 650 - 97.5 ≈ 553 bears
Year 4: 553 - (15% of 553) = 553 - (0.15 * 553) = 553 - 82.95 ≈ 470 bears
Year 5: 470 - (15% of 470) = 470 - (0.15 * 470) = 470 - 70.5 ≈ 400 bears
Year 6: 400 - (15% of 400) = 400 - (0.15 * 400) = 400 - 60 ≈ 340 bears
Year 7: 340 - (15% of 340) = 340 - (0.15 * 340) = 340 - 51 ≈ 289 bears
Therefore, after 7 years, there will be approximately 289 bears in the population. So you are correct.
To calculate the population of bears after 7 years, we need to account for the decrease of 15% per year. We can calculate this by multiplying the current population by (100% - 15%) = 85%.
To find the population after 1 year, we multiply the current population of 900 bears by 85%:
900 x 85% = 765 bears
Now we repeat the process for the next 6 years:
Year 2: 765 x 85% = 649.25 ≈ 649 bears
Year 3: 649 x 85% = 551.65 ≈ 552 bears
Year 4: 552 x 85% = 469.2 ≈ 469 bears
Year 5: 469 x 85% = 398.65 ≈ 399 bears
Year 6: 399 x 85% = 339.15 ≈ 339 bears
Year 7: 339 x 85% = 288.15 ≈ 288 bears
Therefore, after 7 years, there will be approximately 288 bears in the population. Thus, the answer is 288, not 289.