What is the zakat due in case of watering without cost? What is the zakat due in case of watering with cost?

A Zakat giver has an agricultural production at a market value of SAR 300,000. The zakat giver has no accounting books to count the actual production expenses. Assume the zakat receptacle reached the Nisab.
Required:
What is the zakat due in case of watering without cost?
What is the zakat due in case of watering with cost?
A Zakat giver has a commercial building that generated an annual income of SAR 200,000 and incurred actual expenses of SAR 50,000. The book value of the building is SAR 75,000 while its market value is SAR 150,000.
Required: What is the zakat due?
A Single Taxpayer In US Has The Following Information:
Item
US$
Gross Income
500,000
Exclusions
50,000
Deductions For Gross Income
100,000
Itemized Deductions
5,000
Standard Deduction
6,100
Personal Exemptions
3,900
Dependency Exemptions
3,900
Prepayments
75,000

Required: Compute The Tax Due Assuming the Tax Rate Is 20%.