Who amongst the following lives exactly between the fourth floor and the one whose age is 20?

There are three people live between the two vacant floors. The floor numbers of the vacant floors are even – number. The one who is the youngest lives on one of the floors above the floor numbered 5. The one whose age is 40 lives immediately below the one who is the youngest. Vacant floor cannot be 2 and 6 age of the person who lives on the ground floor is the sum of the ages of the persons who lived on the floors numbered 7 and 6. So, the vacant floor is floor no. 8 and other vacant floor is floor no. 4. The one who is the youngest lives on the floor no. 6 and the one whose age is 40 lives on the floor no. 5. The number of floors above E is same as the number of floors between E and C. E lives an odd numbered floor above the floor numbered four.  Only three floors between C and the one whose age is 40. E lives on the floor no. 5, then C lives on the floor no. 1. B lives immediately above F. Only three floors between F and A. Only two floors are there between A and E. D lives on one of the floors below the floor numbered 4. A lives on floor no. 2 and F lives on floor no. 6. B lives on floor no. 7. D lives on floor no. 3.  The age of the person who lives on the ground floor is the sum of the ages of the persons who lived on the floors numbered 7 and 6. The age of the person who lives on the ground floor is not 60. The sum of the ages of the person who lives on second and third floor equals to the age of the person who lives on the ground floor. A’s age is more than D. We know that the age of the person who lives on the ground floor is not 60. We know that A age is more than D. We have two numbers remaining 30 and 50.  The sum of these two is 80. So, A and D’s ages are 50 and 30 respectively. The age of the person who lives on the ground floor is 80.  The age of the person who lives on the ground floor is the sum of the age of the persons who lived on the floors numbered 7 and 6 i.e. 60 + 20 = 80.