Answer:
her to pay you at least $60 but less than $80 to live with the clutter
Step-by-step explanation:
The Coase theorem states that when transaction cost is low, all parties involved will be able to bargain and reach an efficient outcome that benefits both parties. Based on this the efficient solution would be for her to pay you at least $60 but less than $80 to live with the clutter. Making it higher than the cost imposed on you but less than her benefit, thus ultimately benefiting both parties.