Concept:Chain the given ratios by making the common terms equal.Explanation:We have A:B=8:15, B:C=5:8, and C:D=4:5.First, combine A:B and B:C by equalizing B.The LCM of 15 and 5 is 15.Multiply B:C by 3 to get B:C=15:24.Thus A:B:C=8:15:24, so A:C=8:24=1:3.Now combine A:C and C:D by equalizing C.The LCM of 3 and 4 is 12.Multiply A:C by 4 to get A:C=4:12.Multiply C:D by 3 to get C:D=12:15.Hence A:C:D=4:12:15, giving A:D=4:15.Therefore the ratio of A to D is 4:15.Answer:A:D=4:15