A trader bought 10 kg of tea at Rs. 400 per kg. He sold half the quantity at 20% loss and remaining at 10% profit. What was his net profit or loss in percentage?
M can complete 3/4 part of a work in 12 days and N can complete 2/7 part of the same work in 8 days. In how many days will both complete 11/14 part of the total work?