Question 459216
I assume they all fill at the same rate
which is: (.5 pool filled) / (2.5 hrs)
(note that each hose can fill 1/2 pool in 2.5 hrs)
Now add the rates to find time, {{{t}}} for 3 hoses
{{{ .5/2.5 + .5/2.5 + .5/2.5 = 1/t }}}
{{{ 1/5 + 1/5 + 1/5 = 1/t }}}
{{{ 3*(1/5) = 1/t }}}
Multiply both sides by {{{5t}}}
{{{ 3t = 5 }}}
{{{ t = 3/5 }}} hr
{{{ t = (3/5)*60 = 36 }}} min
It takes 36 min to fill the pool with 3 hoses