The 10% vat is taken taken from the selling price of a watch.
To get the 10% vat amount, we will first change 10% into decimal form which is 0.10 since 10% × 100 = 0.10
and then now, we will multiply 0.10 to the selling price which is 825.
825 × 0.10 = 82.50
The amount of 82.50 is for the vat.
Now, we will subtract the vat amount from the selling price to get the basic price of a watch.
825 - 82.50 = 742.50
Therefore, the basic price of a watch is 742.50