<prompt> Translate the following text to SwahiliThus, for example, if the volume in the first quintile were to double, total cost would increase by 29 percent.  <response>: Kwa mfano, ikiwa kiasi cha bidhaa katika quintile ya kwanza ingekuwa mara mbili, gharama ya jumla ingekuwa kuongezeka kwa asilimia 29. 