Find the triplicate ratio of 2a : 3b

Find the sub-duplicate ratio of 9x²a⁴ : 25y⁶b²

Find the reciprocal ratio of 3 : 5

Find the ratio compounded of the duplicate ratio of 5 : 6, the reciprocal ratio of 25 : 42 and the sub-duplicate ratio of 36 : 49.