Question 795644
Add their rates of working
Maria's rate:
( 1 order filled ) / ( 3 hrs )
Tom's rate:
( 1 order filled ) / ( 4 hrs )
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Let {{{ t }}} = time in hrs for them to
fill 1 order working together
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{{{ 1/3 + 1/4 = 1/t }}}
Multiply both sides by {{{ 12t }}}
{{{ 4t + 3t = 12 }}}
{{{ 7t = 12 }}}
{{{ t = 1.714 }}}
{{{ .714*60 = 43 }}}
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It will take them 1 hr and 43 min working together
check answer:
{{{ 1/3 + 1/4 = 1/t }}}
{{{ 1/3 + 1/4 = 1/1.714 }}}
{{{ .333 + .25 = .58333 }}}
{{{ .58333 = .58333 }}}
OK