Final answer:
The population when the otters were reintroduced (at t = 0) is 10.
Step-by-step explanation:
To find the population when the otters were reintroduced (at t = 0), we need to substitute t = 0 into the formula y = 2500 - 2490e^(-0.1t).
Substituting t = 0, we have y = 2500 - 2490e^(0).
Since any number raised to the power of 0 is 1, we have y = 2500 - 2490(1) = 2500 - 2490 = 10.
Therefore, the population when the otters were reintroduced (at t = 0) is 10.