Concept:Probability that the problem is solved = 1 minus probability that none solves it.Explanation:Chances of solving: A:31​,B:51​,C:21​.Probability that A does not solve: 1−31​=32​.Probability that B does not solve: 1−51​=54​.Probability that C does not solve: 1−21​=21​.Assuming independence, probability that none solves: 32​×54​×21​=308​=154​.Therefore, probability that the problem is solved: 1−154​=1511​.Answer:1511​