Answer:
The numbers you're looking for are 18 and 24. Here's why:
The Highest Common Factor (HCF) of two numbers is the largest number that divides both of them without leaving a remainder. In this case, the HCF is 6, so both numbers must be multiples of 6.
The Least Common Multiple (LCM) of two numbers is the smallest number that is a multiple of both of them. In this case, the LCM is 72.
The multiples of 6 that are less than 30 are 6, 12, 18, and 24. Of these, the pair that has an LCM of 72 is 18 and 24 because 72 is the least common multiple of 18 and 24.