Question 794705
Another way to say 2 coats is 
to paint the fence twice
Also, that is the same as painting
2 identical fences
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Tom's rate is:
{{{ 1/8 }}} = ( 1 fence ) / ( 8 hrs )
Huck's rate is:
{{{ 1/5 }}} = ( 1 fence ) / ( 5 hrs )
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Let {{{ t }}} = the time in hrs for them
to paint 2 fences
{{{ 2/t }}} = ( 2 fences ) / ( t hrs )
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{{{ 1/8 + 1/5 = 2/t }}}
Multiply both sides by {{{ 40t }}}
{{{ 5t + 8t = 80 }}}
{{{ 13t = 80 }}}
{{{ t = 6.154 }}}
It will take them 6.154 hrs