Let x represent the number of students that studied in the second most popular country. If 5770 more students studied in the most popular host country than in the second most popular host country, it means that the number of students that studied in the most popular host country is
x + 5770
If the total number of students is 53910, it means that
x + 5770 + x = 53910
2x + 5770 = 53910
2x = 53910 - 5770 = 48140
x = 48140/2
x = 24070
Thus,
the number of students that studied in the second most popular host country is 24070
the number of students that studied in the most popular host country is
24070 + 5770 = 29840