Explanation:

Reduced price = (Ax /100n) per kg
Original price = (Ax /100 - x)n per kg
Where,
'x'  is the percentage of reduction in the price of an article = 20%
'n'  is the increased weight after the reduction of price = 2 kg
'A'  is the price of increased weight = ? 30
The reduced price of rice = 30 x 20 /100 x 2 = ? 3 per kg.
and
The original price of rice = 30 x 20 /100 - 20)2 = 15/4
= 3 3/4  per kg