Minimum number of rooms required =Total number of participants /HCF (60,84,108)
Prime factorization of 60, 84 and 108 is:
60 = 22 × 3 × 5
84 = 22 × 3 × 7
108 = 22 × 33
HCF = product of smallest power of each common prime factor in the numbers = 22 × 3 = 12
Total number of participants = 60 + 84 + 108 = 252
Therefore, minimum number of rooms required = 252/12 = 21
Thus, minimum number of rooms required is 21