Which of the problems of Latin America were the Cuban and Nicaraguan revolutionaries able to solve?

The revolutionaries in Cuba have achieved a number of successes:

The medicine. Cuba has some of the lowest infant mortality rates in the world and one of the highest life expectancies.
Education. Good quality education, foreign students are trained, Cuban specialists work in many countries.
Safety. In Cuba, crime is low, there are few murders, drug addiction and other problems.
Stratification by income. In Cuba, it is low, Honduras and Guatemala, for example, very high.

In Nicaragua, the successes of 1979-1990 and after 2006 under Ortega are not so impressive, but there is progress in these areas.