The number of years value isn't given, we could use an hypothetical value, which can be substituted for the correct number of years given in your exercise in other to find the exact answer.
Using a t value of 10 years
Answer:
651558
Explanation:
Given that:
Initial population, P0= 400,000
Growth rate, r = 5%
Using the relation :
P(t) = P0 * (1 + r)^t
t = number of years = 10
P(10) = 400000 * (1 + 0.05)^10
P(10) = 400000 * (1.05)^10
P(10) = 400000 * 1.628894626777
P(10) = 651557.8507
= 651558 nearest whole number.
Recall that, the t value used is hypothetical and should be replaces with te exact value given in your question.