Three men start together to travel the same way around a circular track of 11 kilometres in circumference. Their speeds are 4, 5 1/2 and 8 kilometres per hour, respectively. When will they meet at the starting point?
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?