Answer:
4.04 x 10^0 people/km^2 (x 10^0 is fairly redundant but if the answer is required in standard form then include it)
Step-by-step explanation:
Population Density = Population/Area
= 3.11 x 10^7 / 7.69 x 10^6
= 31,100,000 / 7,690,000
= 3110 / 769
= 4.04
= 4.04 x 10^0