Pipes A, B and C can fill a tank in 15, 30 and 40 hours, respectively. Pipes A, B and C are opened at 6 a.m., 8 a.m. and 10 a.m., respectively, on the same day. When will the tank be full?
On a marked price, the difference of selling prices with a discount of 35% and two successive discounts of 20% and 15%, is Rs. 504. The marked price of the article (in Rs.) is: