What is the ruling on a partnership with 20,000 dirhams in exchange for 10% of the daily profits in the cardboard trade? Is this condition unfair? What are the regulations for a blessed partnership? And is zakat obligatory on this money every year, provided it reaches the nisab?

Paying money to your cousin to invest it in the cardboard trade is a permissible mudarabah (profit-sharing) partnership, provided that the profit ratio is shared between you, that neither of you stipulates a fixed amount of profit for himself, and that the working partner does not guarantee the capital. Blessings in trade come from honesty and avoiding betrayal, for Allah is the third of the two partners as long as neither betrays the other, and if they are truthful and transparent, their transaction will be blessed.