The absolute difference of two real numbers x, y is given by |x - y|. Now we need to know the population of Chandler and Gilbert after 10 years.
Chandler: We have that after ten years the population is 220,000
Gilbert: after ten years the population is
the 1 year after: 200,000 + 20,000 = 220,000
the 2 year after: 220,000 + 22,000 = 242,000
the 3 year after: 242,000 + 24,200 = 266,200
the 4 year after: 266,200 + 26,620 = 292,820
the 5 year after: 292,820 + 29,282 = 322,102
the 6 year after: 322,102 + 32,210.2 = 354,312.2
the 7 year after: 354,312.2 + 35,431.22 = 389,743.42
the 8 year after: 389,743.42 + 38,974.342 = 428,717.762
the 9 year after: 428,717.762 + 42,871.7762 = 471,589.5382
the 10 year after: 471,589.5382 + 47,158.95382 = 518,748.90764
a. So the absolute difference is |518,748.90764 - 220,000 |= 298,748.90764
The relative difference is given bu the formula

in this case we have that the relative difference is

b. 0.57590272