no problem, (used as a conventional reply to a request or to express confirmation, affirmation, or gratitude).
Origin: 1350–1400;Middle Englishprobleme < Latinproblēma < Greekpróblēma orig., obstacle, (akin to probállein to throw or lay before), equivalent to pro-pro-2 + -blē-, variant stem of bállein to throw (cf. parabola) + -ma noun suffix of result
1382, "a difficult question proposed for solution," from O.Fr. problème (14c.), from L. problema, from Gk. problema "a problem, a question," lit. "thing put forward," from proballein "propose," from pro "forward" + ballein "to throw" (see ballistics). Problem child first recorded 1920.