Question 1041930
Brenda's rate of working:
[ 1 attic cleaned ] / [ 15 hrs ]
Danielle's rate of working:
[ 1 attic cleaned ] / [ 13 hrs ]
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Add their rates of working to get
their rate working together
Let {{{ t }}} = time in hrs for them to
clean the attic working together
{{{ 1/15 + 1/13 = 1/t }}}
Multiply both sides by {{{ 13*15t }}}
{{{ 13t + 15t = 13*15 }}}
{{{ 13t + 15t = 195 }}}
{{{ 28t = 195 }}}
{{{ t = 6.964 }}} hrs
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check the answer:
{{{ 1/15 + 1/13 = 1/t }}}
{{{ .0667 + .0769 = 1/6.964 }}}
{{{ .1436 = .1436 }}}
OK