The results of a survey of 41 students and the foreign language they are studying are shown in the two- way frequency table.
Language
Gender Chinese French Spanish Total
Girl
3
9
14
26
Boy
2
2.
11
15
Total
5
11
25
41
What fraction of the surveyed students are taking Chinese?
of the surveyed students are taking Chinese.

We know that 80% of the stamps are US and Mexican. 
The US stamps are 3 times the Mexican stamps. That means that of the 80%, Mexicans comprised of the 20% and US comprised of the 60% to satisfy the relationship of their ratios. 

Therefore, 60% of Michelle's collection is made up of US stamps.