The annual income of A is 20% more than annual income of B and the annual income of C is 15% more than the annual income of A. What is the sum of the monthly incomes of A, B and C if the monthly income of A is Rs. 1200 ?

The rate of increase of population of city is 10% per annum. If in the year 2005, its populations was 80000. What will be its population in the year 2008 ?

In a class, the average age of 20 students is 15 years. If the teacher is also included in the class, the average age increases by one year. What is the age of the teacher ?