A wholesaler sells a watch to a retailer at a gain of 35% and the retailer sells it to a customer at a loss of 25%. If the customer pays Rs 2379.375, what had it cost the wholesaler?

For the wholesaler,

Let the cost price = Rs. $$100x$$

With profit of 35%, Selling price = $$\frac{135}{100} \times 100x = Rs. 135x$$

For the retailer,

Cost price = Rs. $$135x$$

With a loss of 25%, Selling price = $$\frac{75}{100} \times 135x = Rs. 101.25x$$

For the customer,

Cost price = $$101.25x = 2379.375$$

=> $$x = \frac{2379.375}{101.25} = 23.5$$

$$\therefore$$ Cost price for retailer = $$100 \times 23.5 = Rs 2350$$