The average age of 30 students of a class is 12 years. The average age of a group of 5 of the students is 10 years and that of another group of 5 of them is 14 years. What is the average age of the remaining students?
A man willed his property to his three sons ---- to the youngest he gave Rs. 698.49, to the second 3.4 as much as to the youngest, and to the eldest 3.7 times as much as to the second. What was the value of his estate?
The ratio of the age of a man and his wife is 4 : 3. After 4 years, this ratio will be 9 : 7. If at the time of the marriage, the ratio was 5 : 3, then how many years ago they were married?