Answer: 40 million
Explanation:
Number of families that had TVs in their home in 1980s = 60 million
Number of families that had TVs in their home in 2015 = 100 million
To calculate the increase in TVs that were there in 2015, we subtract the number of families that had TVs in their home in 1980s which was 60 million from the number of families that had TVs in their home in 2015 which was 100 million. This can be expressed as:
= 100 million - 60 million
= 40 million