The following bar graph shows the sales (in thousands) of motor bikes by the factories, F1, F2, F3 and F4 in 2017, 2018 and 2019. What is the ratio of total sales of F1 to that of F4 across all years?

10 : 9 3 : 7 9 : 11 11 : 10

11 : 10

Total sale of F1    :   Total sale of F4 ( 65 + 72 + 83 )  :  ( 63 + 68 + 69 )          220           :          200            11           :           10