A sum of money amounts to Rs. 6690 after 3 years and Rs.10,035 after 6 years on compound interest. The sum is :
A group of 240 persons consisting of students and teachers is travelling in a train. For every 15 students, there is one teacher. Then, the number of teachers is
A father is 3 times as old as his son. Five years back he was 7 times as old as his son. The age of the son is