The ratio of a two-digit number and the sum of the digits of that number is 5 : 1 . If the digit in the unit's place is one more than the digit in the ten's place, what is the number ?

A milkman adds 4 litres of water to 16 litres of milk and another 9 litres of water to 27 litres of milk. What will be the ratio of the fraction of milk in the two mixtures ?

'A' began a business with Rs 800 and was joined afterwards by ' B ' with Rs 600. When did ' B ' join if the profit at the end of the year was divided in the ratio 4 : 1 ?