Question 362533
Let 20 drinks = {{{1}}} task
Let {{{x}}} = the time it takes them working
together to mix 20 drinks or {{{1}}} task
Steven's rate of mixing = {{{1/5}}}
Sue's rate of mixing = {{{1/10}}}
Jack's rate of mixing = {{{1/15}}}
-----------------
Working together, their combined rate is:
{{{1/5 + 1/10 + 1/15 = 1/x}}}
Multiply both sides by {{{30x}}}
{{{6x + 3x + 2x = 30}}}
{{{11x = 30}}}
{{{x = 2.73}}} min