What is the ruling on installment sales with an increase in the price?

Question:
A man wanted to buy a house, but he did not have enough money to purchase it, so he went to borrow. They told him: We do not lend, but we will buy the house, and then you pay us in installments, with an increase in the price. For example, the cost of buying the house is forty, and you pay us forty-five. They said: This is equivalent to the period during which our money was idle?

Answer:
There is no harm if they sell him a commodity for an increased price; there is no harm. This is a sale for a deferred period. If they buy the house and then sell it to him for a known price at a known deferred time, in one lump sum or in installments, it is valid. The scholars have explicitly stated this. If the merchant buys the house for forty thousand and sells it to the one in need for forty-five thousand, or fifty thousand, at deferred times, or at one deferred time, there is no harm in that. Or if he sells him bags of sugar, or bags of food, at a known deferred time, there is no harm.

Question:...؟

Answer: There is no harm if they buy the house for him on their own account, and then sell it to him; there is no harm.