According to chart,
28 + x + 14 + x + 6 + 2x = 100
4x = 100  -  48
x = 52/4 = 13% = number of persons visiting USA
number of persons visiting Australia = (13 + 6) = 19%
number of persons visiting Japan = 2 * 13 = 26% 
| Country | Percentage | Number of persons | 
| India | 28% | 2240 | 
| USA | 13% | 1040 | 
| Canada | 14% | 1120 | 
| Australia | 19% | 1520 | 
| Japan | 26% | 2080 | 
Number of persons visiting Canada = 14% of 8000
Number of persons visiting Australia and USA together = (19 + 13)% of 8000 = 32% of 8000
Required ratio = 14% of 8000 : 32% of 8000 = 14 : 32 = 7 : 16
Alternate method :
Required ratio = 14 : (19 + 13) = 14 : 32 = 7 : 16