Question

The Pribilof Islands in Alaska supports about half ofthe global population of Northern fur seals. St. PaulIsland, the largest of the Pribilof Islands, has 12 furseal rookeries (breeding places). In 1961, to estimatethe fur seal pup population in the Gorbotch rookery,4963 fur seal pups were tagged in early August. In lateAugust, a sample of 900 pups was observed and 218 ofthese were found to have been previously tagged.Estimate the total number of fur seal pups in thisrookery.

Answer 1

20,489

Step-by-step explanation:

Let the total number of seal pups = x

• Out of x pups, 4963 fur seal pups were tagged in early August.

,

• On observation, out of 900 pups, 218 were tagged.

We can express this as a ratio of total to tagged pups:

`\frac{\text{Total}}{\text{Tagged}}\implies(x)/(4963)=(900)/(218)`

We solve for x.

`\begin{gathered} (x)/(4963)=(900)/(218) \\ \text{Multiply both sides by 4963} \\ (x)/(4963)*4963=(900)/(218)*4963 \\ x=20489.4 \\ \text{Approximate by rounding to the nearest whole number} \\ x\approx20,489 \end{gathered}`

The total number of fur seal pups in this rookery is approximately 20,489.