Is it permissible to purchase a minibus from an investor by paying him double its price in installments?

If two parties agree that the owner will sell the car after purchasing it and it enters into his possession and guarantee, then he sells it to another party for a specific price (more or less than the purchase price, whether the price is immediate or deferred), there is no harm in that. This is because profit is permissible, and time has a share in the price. However, selling the car before possessing it is not permissible because it is selling what one does not own. Furthermore, the transaction is not permissible if the car's price is unknown to the buyer at the time of the contract.