Use logs to determine the number of years until the population drops to 15,390 organisms. round answer to 2 decimal places.

  4.47 years

Step-by-step explanation:

Fill in the numbers and solve for t.

  P = a·b^t

  15390 = 19000·0.954^t

  15390/19000 = 0.954^t . . . . . divide by 19000

  0.81 = 0.954^t . . . . . . . . . . . . . simplify

  log(0.81) = t·log(0.954) . . . . . . take the log

  t = log(0.81)/log(0.954) . . . . . . divide by the coefficient of t

  t ≈ 4.47

It will take about 4.47 years for the population to drop to 15390 organisms.

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A graphing calculator can be another way to solve a problem like this.