A population of cheetahs decreases 40% each year.

What is the decay factor b in this situation?

Use this equation y = a (1 - b) ^x

Where a is the initial population and b is the decay factor: 40/100 = 0.4

Therefore, the answer is that the decay factor b is 0.4.

This table shows some figures using the decay factor.

year decrease population

0 0 a (1 - 0.4) ^0 = a

1 a*0.4 a (1 - 0.4) ^1 = a*0.6 = 0.6a

2 0.6a*0.4 a (1 - 0.4) ^2 = a (0.6) ^2 = 0.36a

3 0.36a*0.4 a (1 - 0.4) ^3 = a (0.6) ^3 = 0.216a