Question 177029
If Steven can mix 20 drinks in 5 minutes, Sue can mix 20 drinks in 10 minutes, and Jack can mix 20 drinks in 15 minutes, how much time does it take all 3 of them working together to mix 20 drinks/
;
let t = time required to mix 20 drinks working together:
:
let the completed job =  1; (the mixing of 20 drinks)
;
{{{t/5}}} + {{{t/10}}} + {{{t/15}}} = 1
mult eq by 30, results:
6t + 3t + 2t = 30
11t = 30
t = {{{30/11}}}
t = 2.727 min or 2 + .727(60) = 2 min 43.6 sec 
:
:
Check solution
{{{2.727/5}}} + {{{2.727/10}}} + {{{2.727/15}}} =
.5454 + .2727 + .1818 = .9999 ~ 1 
;
SORRY ABOUT THE SCREW-UP HERE