The sum of two numbers is 42. The smaller number is 18 less than the larger number. What are the numbers?

Http://www.americanrhetoric.com/speeches/mlkihaveadream.htm "I Have a Dream" is a public speech delivered by American civil rights activist Martin Luther King, Jr. during the March on Washington for Jobs and Freedom on August 28, 1963, in which he calls for an end to racism in the United States and called for civil and economic rights. Delivered to over 250,000 civil rights supporters from the steps of the Lincoln Memorial in Washington, D.C., the speech was a defining moment of the American Civil Rights Movement.