the current population of a city is 45000 and is increasing according to P=45000(1+t)^n and n=number of years. if the rate of increase is 7.5% how long will it take the population to double?

Answer 1

90000 = 45000(1.075)^n
2 = 1.075^n
log both sides
log 2 = nlog1.075
n = log2/log1.075 = appr 8.58 years