Question 454110
Add their rates of working
Dana's rate:
( 1 fence) / ( 60 min )
Fran's rate:
( 1 fence) / ( 40 min )
{{{ 1/60 + 1/40 = 1/x }}}
Multiply both sides by {{{ 120x}}}
{{{ 2x + 3x = 120 }}}
{{{ 5x = 120 }}}
{{{ x = 24 }}}
It will take them 24 min working together