The selling price of one article allowing a discount of 15% on its cost price, is the same as the selling price of another article after allowing a discount of 25% on its cost price. If the sum of the cost price of both the articles is Rs. 640, then find the selling price of each article.

\[\begin{array}{*{20}{c}} {}&{\text{I}}&{{\text{II}}} \\ {{\text{Cost price}}}&{{{20}_{ \times 3}}}&{{4_{ \times 17}}} \\ {{\text{Discount}}}&{ - 3}&{ - 1} \\ {{\text{Selling price}}}&{{{17}_{ \times 3}}}&{{3_{ \times 17}}} \end{array}\]
Cost price = 60 + 68 = 128 unit
128 unit → 640
1 unit → 5
Selling price = 51 unit = 51 × 25 = Rs. 255