Question 572862
Let {{{ t }}} = time in minutes for 2nd pump alone to drain pool
Add the rates of pumping of each pump to get
the rate of both pumping together
Rate of 1st pump:
{{{ 1/11 }}} ( 1 pool drained/ 11 min )
Rate of 2nd pump:
{{{ 1/t }}} ( 1 pool drained / t min )
---------------------------
{{{ 1/11 + 1/t = 1/8 }}}
Multiply both sides by {{{ 88t }}}
{{{ 8t + 88 = 11t }}}
{{{ 3t = 88 }}}
{{{ t = 29.333 }}}
{{{ .333*60 = 20 }}}
the 2nd pump takes 29 min and 20 sec to drain pool by itself
check answer:
{{{ 1/11 + 1/29.333 = 1/8 }}}
{{{ .09091 + .034091 = .125 }}}
{{{ .125001 = .125 }}}
error due to rounding off