A deer population is declining with a decay constant of magnitude 0.327 year. After 6.00 years,
(a) by what factor has the population declined?

Here, the ratio of final population to inital population will be less than one (1). If, for instance, it were 0.2, then the population would have decreased by a factor of 5 (because 0.2 = 1/5). That is, for every 5 original animals, we end up with only one.

And the reciprocal of this, (0.2), gives the factor 5. Now try the question, using this information before going on to the solution.

(b) by what percentage has it declined?

If you start with 100 animals, then after 6 years, there would be 100/7.11 = 14.1 deer. Round this off to 14, and calculate the percentage decline in the population.

Try it before going to the solution.

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