It's on the picture

African americans at the time just came out of slavery and needed money to provide for there families. so they joined for the money mainly.

Photographs of soviet missiles from 1950

the imf provides economic advice and loans to developing countries.

economic advice:

policy advice to governments and central banks based on analysis of economic trends and cross-country experiences; research, statistics, forecasts, and analysis based on tracking of global, regional, and individual economies and markets; technical assistance and training to countries improve the management of their economies.

loans:

loans to countries overcome economic difficulties; concessional loans to fight poverty.

these are the goals the fund wants to achive.