An egg seller mixes duck’s eggs with hen’s eggs in the ratio 56 ∶ 22. He sells the mixed 351 eggs for a price of Rs. 2704.5. What was the difference in the prices of the hen’s egg and duck’s egg, if they had been mixed in the reverse ratio, i.e., 22 ∶ 56, the mixture would have costed Rs. 382.5 more.