Answer:
NRV before writing-off = $191500
NRV after writing off = $198800
Explanation:
Lets first understand what net realizable value is. Net realizable value is the remaining/realizable value of an asset after having subtracted selling or completion costs. In case of receivables, the net realizable value would be the residual value of receivables expected to be received after subtracting any allowances for doubtful debts or un-collectible accounts such as bad-debt (i.e receivables unable to be collected).
NRV before writing-off = $200000 - $8500
NRV before writing-off = $191500
Now lets calculate NRV after a receivable has been declared as uncollectible.
Since $8500 was just an allowance/estimate and now that actual amount of bad-debt has been discovered, we have to inrease our receivables by the difference of the allowance and bad-debt and that would be the NRV after writing off. I.e $8500 - $1200 =$7300.
NRV after writing off = $191500+ $7300
NRV after writing off = $198800.
This is just like subtracting $1200 from $200000.