if sth works out at sth, you calculate that it will be a particular amount :
[+ adj ]
It'll work out cheaper to travel by bus.
if sth works out at sth, you calculate that it will be a particular amount :
[+ adj ]
It'll work out cheaper to travel by bus.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005