Concept:The probability that the problem is solved is the complement of the event that none of the students solves it.Explanation:Given probabilities: P(A)=21​, P(B)=31​, P(C)=41​, P(D)=51​, P(E)=61​.Assuming independence, probability that none solves = (1−21​)(1−31​)(1−41​)(1−51​)(1−61​).Simplify: 21​×32​×43​×54​×65​=61​.Thus, probability at least one solves = 1−61​=65​.Answer:65​