What percent of the average sales branches B1, B2 and B3 in 2001 is the average sales of branches B1, B3 and B6 in 2000?

Total sales (in thousand numbers) of branches B1, B3 and B6 in 2000
= 80 + 95 + 70
= 245
Average sales (in thousands number) of branches B1, B3 and B6 in 2000
= $$\frac{245}{3}$$
Total sales (in thousands number) of branches B1, B2 and B3 in 2001
= 105 + 65 + 110
= 280
Average sales (in thousand number) of branches B1, B2 and B3 in 2001
$$\eqalign{ & = \frac{280}{3} \cr & \text{So,Required percentage} \cr & = \frac{\frac{245}{3}}{\frac{280}{3}}\times100\% \cr & = \frac{245}{280}\times100 \cr & = 87.5\% \cr} $$