Answer:
29 years
Step-by-step explanation:
The population of the Chinese people is 1.3 bn, and they grow at a rate of 0.49% per year. To get the number of years it requires to reach 1.5 bn, we use this method
after x years, the population will be
1.3 * 1.0049^x
so you just need to solve
1.3 * 1.0049^x = 1.5
1.0049^x = 1.5/1.3
x log 1.0049 = log(1.5/1.3)
x = log(1.5/1.3)/log(1.0049)
x = 0.062 / 0.002122
x = 29.25 years
Therefore, at the rate of 0.49%, the Chinese population of 1.3bn needs 29 years to clock 1.5 bn