Brain-Teaser 472

From The Sunday Times, 14th June 1970 [link]

The monogamous and aptly named state of Swindlonabad has a number of inflexible marital laws, these being that:

(a) Each male citizen must marry on his 21st birthday.

(b) Each married man must contribute on his wedding day and each subsequent birthday to an Inheritance Trust which must be maintained at exactly the number of shekels equal to the square of the number of years he has lived.

(c) When an individual’s trust fund can be precisely divided among all his legitimate unmarried sons, each son receiving a number of shekels equal to the square of that son’s age, the father retires and he and his family are maintained by the state.

Now Abdul the Prolific fathered a child during each year of his married life, and all of these children survived to attend his retirement revels. Although only two of his many children were girls, he complained bitterly that such a misfortune should overtake him twice in a decade. At the time of his retirement only one of his daughters was under the age of ten.

How old were the two daughters at that time?