N2

Bob and Jake are neighbours. During the autumn, it is impossible for cleaning up fall leaves in front of Bob's house without clearing the front of Jake's house*. Bob's marginal benefit from cleaning services is 12-Z where Z is the number of time the cleaning service is used. Jake's marginal benefit is 8-2Z. Marginal cost of using the cleaning service is $16. Find the efficient level of provision of cleaning service. Round your answer to two digits.