Question 401238
Rate of filling = {{{R[1] = 1/10}}} (1 tubful/10 min)
Rate of emptying: {{{R[2] = 1/12}}} (1 tubful/12 min)
Let {{{R[3]}}} = rate with both open
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{{{R[3] = R[1] - R[2]}}}
{{{R[3] = 1/10 - 1/12}}}
{{{R[3] = 6/60 - 5/60}}}
{{{R[3] = 1/60}}}
{{{1/60 = 1/t}}} (1 tubful/t minutes)
{{{t = 60}}} min
It will take 1 hour to fill the tub with drain open