BEST ANSWER :
(iv) a) 3.66 × 10^6
b) 2.714 × 10^6
(iii) 35%.
by question known :
(i) a) 3663900 = 3.6639 × 10^6
= 3.66 × 10^6
{ keep three significant digit }
b) 2714000 = 2.714 × 10^6
(iii) (3663900 - 2714000) ÷ 2714000 × 100%
= 949900 = 2714000 × 100%
= 0.35 × 100%
=35%
.°. the percentage increase in the population from 1965 to 2015 is 35%