How is zakat calculated on a capital of 1,0 riyals from 5 people, with the fund being supported monthly by the same amount for financing cars and furniture and selling a car every two months?

Zakat (definition) is obligatory on cars and furniture intended for trade if a year has passed over them and they have reached the nisab (definition), which is equivalent to 85 grams of pure gold or more. Zakat is calculated by inventorying these assets and estimating their market value, then 2.5% of that value is given. Similarly, money in the cash register is subject to Zakat if it reaches the nisab and a year has passed over it. To calculate Zakat accurately, one can track each amount that has reached the nisab and over which a year has passed, and pay its Zakat separately. Alternatively, one can pay Zakat on all money in the cash register when a year has passed over the first nisab accumulated therein, and this is preferable.