What is the common denominator of 5/24 and 7/18

The answer is 72. Least common multiple means u have to take the multiples of 18 and 24. Multiples of 18 are: 18, 36, 54, 72, 90, 108 and so on Multiples of 24 are: 24, 48, 72, 96, 120 and so on. Now check for the common multiples. Only 72 is the common multiple and the least available common multiple. So, LCM of 18 and 24 = 7