The following bar graph shows the sales of books (in thousands) from six branches of a publishing company during two consecutive years 2018 and 2019.

What is the average sales of all the branches (in thousands) for the year 2018?

80

Total sale of all the branches in year 2018

= 80 + 75 + 95 + 85 + 75 + 70

= 480

Average of sale of all the branches in year 2018 = \(\frac{480}{6}\)

= 80