Question 718810
Let {{{ R }}} = the rate of old copier in ( copy job ) / ( hrs )
Let {{{ 4R }}} = the rate of the new copier
Add the rates to get the rate working together
{{{ R + 4R = 1/12 }}} ( 1/12 means ( 1 copy job ) / ( 12 hrs ) )
{{{ 5R = 1/12 }}}
{{{ R = 1/60 }}}
and
{{{ 4R = 4/60 }}}
{{{ 4R = 1/15 }}}
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The old copier can complete the job in 60 hrs working alone
The new copier can complete the job in 15 hrs working alone