Sentence:  This sum spent for foreign economic aid , the peace corps , food for peace , or any other program to <WSD>solve</WSD> the problems of the underdeveloped countries would be an investment that would pay off in world peace , increased world trade , and prosperity for every country on the globe . 
Meaning of the word marked with <WSD> tags:  find the solution to (a problem or question) or understand the meaning of