Given:
Number of fish sold in 2005 : 3,320,000,000
Number of fish sold in 2006: 4,220,000,000
The number of fish sold in 2005 and 2006 is the sum of the number of fish sold in 2005 and the number sold in 2006.
Thus:
Hence, the best estimate of the number of fish sold in 2005 and 2006 is 7,540,000,000
Answer:
7,540,000,000 (Option B)