Question 877021
Add their rates of painting to get
their rate painting together
1st person:
( 1 wall ) / ( 3 hrs )
2nd person:
( 1 wall ) / ( 2 hrs )
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Working together:
( 1 wall ) / ( t hrs )
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{{{ 1/3 + 1/2 = 1/t }}}
Multiply both sides by {{{ 6t }}}
{{{ 2t + 3t = 6 }}}
{{{ 5t = 6 }}}
{{{ t = 6/5 }}}
{{{ t = 1 + 1/5 }}}
Note that {{{ 1/5 }}} hr = {{{ (1/5)*60 = 12 }}} min
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Working together, it will take
them 1 hr and 12 min