What is the ruling on Friday Ghusl (ritual bath)?
Friday Ghusl is a confirmed Sunna (Prophetic tradition) even if a person wasn`t in a state of Janbah (ritual impurity), or physically unclean. However, one who doesn`t make Ghusl on Friday isn`t sinful for the Prophet (PBUH) said: "It is good for a Muslim to make ablution for Friday prayer, but it is better to make Ghusul. [At-Tirmithi & Abu Dawood].
A person vowed to slaughter a sacrificial animal. Is he permitted to eat from it?
If the vowed sacrificial animal was for the sake of Allah, and the one who vowed didn't specify then its meat should be distributed only among the poor and needy similar to distributing Zakah of Al-Fiter so neither him nor his dependents permitted to eat from; however if his vow was to made a banquet and invititing his relatives and others; then he must bring up as much as he can from its meat for them. In addition, he is permitted to eat from it in a reasonable basis. And Allah Knows Best.
There is a car dealership, and their method of selling is as follows: The customer pays the full price of the car, the car is registered in their name, and another contract is written in which the company commits to refunding the full price of the car to the customer after one year from the purchase date. What is the Islamic ruling on this transaction?
As for purchasing the car, paying its price, and owning it, this is a valid sale with no issue. However, the condition of refunding the price — whether the car is returned to the seller or not — is an invalid condition that nullifies the entire contract. Therefore, this transaction is invalid and not permissible. And Allah Knows Best.
Is it permissible for someone to make a supplication to Allah to marry an already married, or an engaged woman?
No, it isn`t, and the person who does so is sinful before Allah, The Almighty.