Question 40454
Rate of the first pipe is (1/45). The rate of the second pipe is (1/135).
Rate times time yields work, so the you have: (t/45) and (t/135).
{{{(t/45) + (t/135) = 1}}} one job is being done
{{{135(t/45) + 135(t/135) = 135}}}
{{{3t + t = 135}}}
{{{4t = 135}}}
{{{t = 33.75}}}
(0.75)(60) = 45
33 minutes and 45 seconds