For a certain group, aggregate claims are uniformly distributed over (0,10). Insurer A proposes stop-loss coverage with a deductible of 6 for a premium equal to the expected stop-loss claims. Insurer B proposes group coverage with a premium of 7 and a dividend (a premium refund) equal to the excess, if any, of 7k over claims. Calculate k such that the expected cost to the group is equal under both proposals.