D. None of these
A student took five papers in an examination, where the full marks were the same for each paper. His marks in these papers were in the proportion of 6 : 7 : 8 : 9 : 10. In all papers together, the candidate obtained 60% of the total marks. Then the number of papers in which he got more than 50% marks is:
A milkman claims to sell milk at the cost price but actually mixes water and milk in the ratio1 : 4. By selling this product, his revenue is Rs. 600 every day. The amount of milk remains thesame every day. One day his revenue is Rs. 560 by selling the product at its normal fixed price ofRs. 10 per litre. What is the proportion of water in milk on that day ?