Comprehension Passage
The bar graph provided below gives the sales of books (in thousand numbers) from six branches of a publishing company during two consecutive years 2010 and 2011. Answer the questions based on this bar graph.
What is the ratio of the total sales of branch B2 for both years to the total sales of branch B4 for both years ?
1
2 ∶ 3
2
3 ∶ 5
3
4 ∶ 5
4
7 ∶ 9