Question

If the world population grows at a constant rate of 1.8% per annum, how many years will it take to double? A) 17.7 years

Answer 1

Answer:

after 38.8 years it will double

correct option is D 38.8 years

Explanation:

given data

population grows rate = 1.8%

to find out

how many years will it take to double

solution

we consider here initial population is x

so after 1 year population will be = (100% + 1.8% ) x = 1.018 x

and after n year population will be = $1.018^{n} x$

so it will double

2x = $1.018^{n} x$

take log both side

log 2 = n log (1.018)

n = $\frac{log2}{log1.018}$

n = 38.853

so after 38.8 years it will double

correct option is D 38.8 years