A sells an article to B at a gain of 25% B sells it to C at a gain of 20% and C sells it to D at a gain of 10%. If D pays Rs. 330 for it, how much did it cost to A ?

Cost price (CP), Selling price (SP), Gain (G)

Assume CP of A was 100

Then CP for B = 100 +25% of 100

                     = $$ 100 + \frac{25}{100} \times 100 $$

                     = 125

CP for C = 125 + 20% of 125

             = $$ 125 + \frac{20}{100} \times 125 $$

             = 150

CP for D = 150 + 10% of 150

             = $$ 150 + \frac{10}{100} \times 150 $$

             = 165

But D pays Rs 330

therefore, 165 = 330

                  $$ 1 =\frac{330}{165} $$

                 $$ 100 = \frac{330}{165} \times 100 = 200 $$

CP for A = 200