Sales = Output Sold x Price Per Unit =2000 x 10 = Rs 20000.
Now, Value of Output = Sales + Change in Stocks = 20000 + (-50) = Rs 19950.
$GV{{A}{MJ}}$ = Value of Output - Intermediate Cost = Rs (19950 - 10000) = Rs 9950.
Hence, NVAFC = $GV{{A}{MP}}$ - Consumption of Fixed Capital - Net Indirect Tax (Import duty - Subsidy) = 9950 -600 - (400 - 500)
(Where Net Indirect Tax = Import duty - Subsidies) $NV{{A}{FC}}$= Rs 19450.