Question 1064816
Their rate painting together is:
[ 1 fence painted ] / [ 1 hr ]
Tommy's rate painting alone is:
[ 1 fence painted ] / [ 9 hrs }
Let Huck's rate of painting =
[ 1 fence painted ] / [ t hrs ]
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Add their rates of painting to get their rate
painting together
{{{ 1/9 + 1/t = 1/1 }}}
Multiply both sides by {{{ 9t }}}
{{{ t + 9 = 9t }}}
{{{ 8t = 9 }}}
{{{ t = 1.125 }}} hrs
convert hrs to min
{{{ .125*60 = 7.5 }}}
Convert min to sec
{{{ .5*60 = 30 }}}
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By himself, Huck can paint the fence in 1 hr 7 min 30 sec
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check:
{{{ 1/9 + 1/t = 1/1 }}}
{{{ 1/9 + 1/(9/8) = 1/1 }}}
{{{ 1/9 + 8/9 = 1 }}}
{{{ 1 = 1 }}}
OK