15. The population of an endangered bird is decreasing at a rate of 0.75% per year. There are currently about 200,000 birds left in the world. How many years from now will the bird population be extinct?

let's first notice, the center of the hyperbola is at the origin, since the focus points are equidistantly 3 units away from the origin, that also means that the distance "c" from the center to either focus is 3.

it should also be notable that, the traverse axis for this hyperbola is vertical, or namely over the y-axis and therefore, the positive fraction will be the one with y-variable.

the traverse "a" component or distance from the center to either vertex is not 2, is more than 2, so we can safely put it at √5 ≈ 2.24.

the answer is 0052

0 0 5 2

5 0 2 6 3 5

− 0

2 6

− 0

2 6 3

− 2 5 0

1 3 5

− 1 0 0

3 5