The number of a particular in thousands x years after 1972 c

The number of a particular in thousands x years after 1972 can be modeled by f(x)=220(0.879)^x. Estimate the year when the number of these fish reached 93 thousand?

Solution

f(x)=220(0.879)^x x years after 1972

f(x) = 93000

93 = 220 (0.879)^x

0.422 = (0.879)^x

taking ln on both sides:

ln(0.422) = x*ln(0.879)

x = 6.67

Year = 1972 +7th year = 1979

So, in the year 1979 number of fish reached 93000

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