Answer :
Answer: he lived 9 months in Portugal and 5 months in Brazil.
Step-by-step explanation:
Let x represent the number of months he lived in Portugal.
Let y represent the number of months he lived in Brazil.
Wolfrich lived in Portugal and Brazil for a total period of 14 months in order to learn Portuguese. This means that
x + y = 14
He learned an average of 130 new words per month when he lived in Portugal and an average of 150 new words per month when he lived in Brazil. In total, he learned 1920 new words. This means that
130x + 150y = 1920- - - - - - - - - - - 1
Substituting x = 14 - y into equation 1, it becomes
130(14 - y) + 150y = 1920
1820 - 130y + 150y = 1920
- 130y + 150y = 1920 - 1820
20y = 100
y = 100/20
y = 5
x = 14 - y = 14 - 5
x = 9