Question

A population of 1,750 cheetahs decreases by 11% per year. How many cheetahs will there be in the population after 10 years? Round your answer to the nearest whole number.
A. 4969

B. 486

C. 546

D. 1640

Answer 1

The answer is C. 546.

If a population decreases by 11%, that means that 89% (100% - 11% = 89%) of cheetahs remains each number. 89% can be expressed as 0.89, so to calculate the change of the population, we must each year multiply the number of cheetahs by 0.89.

After 1 year:     1750 * 0.89 ≈ 1558
After 2 years:  1558 * 0.89 ≈ 1387
After 3 years:  1387 * 0.89 ≈ 1234
After 4 years:  1234 * 0.89 ≈ 1098
After 5 years:  1098 * 0.89 ≈ 977
After 6 years:  977 * 0.89 ≈ 870
After 7 years:  870 * 0.89 ≈ 774
After 8 years:  774 * 0.89 ≈ 689
After 9 years:  689 * 0.89 ≈ 613
After 10 years:  613 * 0.89 ≈ 546