Question 1152437


let  Marco's time be {{{x}}}, and  Cliff's time will be {{{2x}}}


Working together, it takes them {{{6}}} hours; so, rates are

{{{1/x + 1/(2x) = 1/6}}}........LCD {{{6x}}}

{{{6/6x + 3/6x = x/6x}}}

{{{9/6x = x/6x}}}

{{{x=9}}}


Answer:  It will take {{{9 }}}hours   to complete the job working alone.