Experts pls help me to solve thsi question and explain the formula ised for this methods...

Dear Student,

a. Value of Output = Sales + Change in Stock
        = 800 + 100
        = 900

b. Gross value added at market price(GVAmp ) = Value of Output - Intermediate Consumption
                 = 900 - 200
                 = 700
c. Net Value added at market price(NVAmp ) = GVAmp - Depreciation
                = 700 - 50 (consumption of fixed capital)
                = 650
d. Net Value added at factor cost = NVAmp - Net indirect tax
                   = 650 - (75-25)
                   = 600

Regards,