<prompt> Translate the following text to EnglishKama kiasi cha jumla, badala ya vipande kwa kila mtu, walikuwa kuonyeshwa juu ya mhimili wima, basi Y-intercepts ingekuwa kubaki bila kubadilika lakini curves gharama itakuwa sambamba.  <response>: If total volume, instead of pieces per capita, were displayed on the vertical axis, then the Y-intercepts would remain unchanged but the cost curves would be parallel. 