Study the given bar graph and answer the question that follows. The bar graph shows the production of table fans in a factory for one week.

The ratio of the total production of table fans on Tuesday and Wednesday together to that on Thursday and Friday together is:

2 : 1

Total production of table fans on Tuesday and Wednesday   :  total production of table fans on Thursday and Friday

  ( 510  +  390 )  :  ( 150 + 300 )

        900            :       450

          2              :         1