Let box A, box B and box C be the three boxes respectively.The given event is a Compound Event which can be written as: [(1G from box A) and (1R from box B) and (1R from box C)] or [(1R from box A) and (1G from box B) and (1R from box C)] or [(1R from box A) and (1R from box B) and (1G from box C)] ∴P=(