Question 1039878
Add their rates of working to get their
rate working together
1st painter's rate:
( 1 house painted ) / ( 4 days )
Let {{{ 1/t }}} = the 2nd painter's rate of painting
which is ( 1 house painted ) / ( t days )
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{{{ 1/4 + 1/t = 1/3 }}}
Multiply both sides by {{{ 12t }}}
{{{ 3t + 12 = 4t }}}
{{{ t = 12 }}}
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The 2nd painter, working alone, finishes the house in 12 days