A manufacturer sells an article to a wholesale dealer at a profit of 10% . The wholesale dealer sells it to a shopkeeper at 20% profit. The shop - keeper sells it to a customer for Rs. 56100 at a loss of 15% . Then the cost price of the article to the manufacturer is = ?

$$\eqalign{ & = \left( {\frac{{56100 \times 100 \times 100 \times 100}}{{\left( {100 - 15} \right) \times \left( {100 + 10} \right) \times \left( {100 + 20} \right)}}} \right) \cr & = \left( {\frac{{56100 \times 100 \times 100 \times 100}}{{85 \times 110 \times 120}}} \right) \cr & = {\text{Rs}}{\text{.}}\,50000 \cr} $$