Initial population (P): 24,000
Growing rate per year(r) : 1.8 % = 0.018 in decimal form ( divided by 100)
We have to apply the poupulation growth formula:
A = P (1+ r )^t
Where :
A = population after t years
t= years
Replacing with the values given:
56,000 = 24,000 (1+0.018)^t
Solve for t:
56,000/24,000 = 1.018 ^t
7/3 = 1.018^t
Apply ln to both sides:
ln 7/3 = ln 1.018 ^t
ln 7/3 = t (ln 1.018)
ln 7/3 / ln 1.018 = t
t= 47.49 = 47 years and a half