A study was made for the number of persons of different age group visited in a library in a week which is shown in the histogram. Study the histogram and answer the question given below.

The ratio of the number of persons in the age groups 15-20 years and 20-25 years together, to the number of persons in the age groups 30-35 years and 35-40 years together, is:

14 : 9

Number of persons in the age groups 15-20 years and 20-25 years  :   Number of persons in the age groups 30-35 years and 35-40 years 

( 300 + 400 )  :  ( 350 + 100 )

       700         :         450

         14         :          9