
Home > CAAC > Chapter 9 > Lesson 9.1.1 > Problem 9-7
9-7.
Let n = the number of countries in North America.
2 n = number of countries in Europe
2 n + 7 = the number of countries in Africa
The total number of countries in all three continents is 122.
n + (2n) + (2n + 7) = 122
n = 23
So, there are 23 countries in North America.
Remember to find the number of countries in Europe and Africa.