Is it permissible to work in appraising car prices and submitting them in writing to usurious banks to enable customers to obtain loans for purchasing cars, or to answer inquiries from usurious banks over the phone regarding car prices?

1. Cooperating with interest-based banks in appraising car prices is not permissible because it falls under cooperating in sin. It is an assistance to the forbidden usurious contract, and Islamic law has prohibited assisting in sin.

2. Opening an office to appraise car prices for those wishing to purchase them is permissible, as long as it does not involve appraising prices for forbidden contracts, such as those conducted by banks and interest-based institutions. However, dealing directly with those wishing to purchase from the seller is a permissible act.