Which of the speeds is higher and how much is 72km / h or 30m / s?

To answer the question, you must translate either 72 km / h in m / s or 30 m / s in km / h.
Let’s convert 72 km / h to m / s. 1h = 3600s.
72 * 1000/ 3600s  = 20m / s
Now we know that 72 km / h = 20m / s
Let’s compare 20m / s and 30m / s, we will see that 30m / s is more than 20m / s.
To find out how many times 30/20 = 1.5.
Answer: 30m / s is 1.5 times more than 75km / h.