Bonus question: Why is it the fathers favorite day?

1. Dad is six times older than his youngest daughter.

2. The adopted daughters' age in days is 100 times her adopted mother's age in years.

3. In three years the dad will be exactly three times the difference in age between him and his younger wife.

4. The age of the two parents together is one less than ten times the eldest daughter's age.

5. The combined age of all four family members in whole years is seventy-one.

Note: Ages are to be taken in years unless otherwise stated and assume there is no leap year.