Is it permissible to take money from friends to pay for an electrical deal purchased on credit and to speculate with their money in the market using the same commodity? Is it permissible to change the price of the commodity from its purchase price? Is it necessary to inform them of the purchase and sale prices? How are the profits distributed? And what is the correct formula for a Mudarabah contract in this case?

Mudarabah (definition) is a contract between two parties: a capital provider and a worker who trades with the capital. They share the profit according to their agreement, and each party loses what they contributed if a loss occurs. The worker is entrusted with the Mudarabah capital and is only liable for loss due to transgression or negligence. It is not permissible for the Mudarib (worker) to purchase goods he owns with the Mudarabah capital, except with the permission of the capital provider and at market price. If he favors himself, he must guarantee the increase to the capital provider.