There are 60/6 = 10 multiples of 6 in the set, and 60/10 = 6 multiples of 10. Of these multiples, 30 and 60 are multiples of both 6 and 10. It means that the set {multiples of 6 OR multiples of 10 from 1 to 60} contains 10 + 6 - 2 = 14 numbers. Therefore, the probability under the problem's question is P == = 0.2333333... ~ 23.33% (approximately). ANSWER