(d) Let one's and ten's digit be x and y, respectively. Then, Number = 10y + x From Statement I, (10x + y) - (10y + x) = 9 ⇒ x - y = 1 From Statement II, x + y = 7 From Statement III, x - y = 1 ∴ Number can be found using Statements II and either I or III.