The points a, b,c and d lie in a straight line. ad=82cm the ratio of the distance ab to bc is 2: 5. the ratio of distance bc to cd 3: 4. find the distance bc

If we had AB: BC: CD, we could easily have solved that problem. In order to combine these ratios, we need to have the same number for BC. We can create this number by finding LCM (Least Common Multiple) for 5 and 3, which is 15. Then, we can write ratios of AB:BC = 6:15 and BC:CD=15:20. Now, we can easily combine these ratios. AB:BC:CD = 6:15:20. Then, 6k+15k+20k = 82 and k=2 cm. And BC = 30 cm