Question 129873
Steven can do 1/5 of the job in 1 minute, Sue 1/10 and Jack 1/15 in 1 minute.
Let j= the job.
1/5 + 1/10 + 1/15
6/30 + 3/30 + 2/30 = 11/30 of the job in 1 minute.
30/11= 2 8/11 minutes to mix 20 drinks together.
2 min 43.6 sec.
.
Ed