The age of a father is twice that of the elder son. Ten years hence the age of the father will be three times of that of the younger son. If the difference of ages of the two sons is 15years, the age of the fathers
Sum of the age A and B at present is 7 times the difference in their age. After five years, the sum of their ages will be 9 times the difference in their ages, the present age of he elder of the tow is therefore