Answer:
The discount was rs 80.
Explanation:
The item started at an original undiscounted price of x.
Then a 5% discount was applied. The price is now 0.95x.
Then a 10% VAT was applied. The price is now 1.1(0.95x).
The price is now rs 1672.
1.1(0.95x) = 1672
Divide both sides by 1.1 and by 0.95.
x = 1600
The original price was rs 1600.
5% of rs 1600 = 0.05 * rs 1600 = rs 80
The discount was rs 80.