if A fills a tank in 30mins,and B fills the same tank in 20mins,and C emptys it in 40min ,if A,B,C works together how much time will the tank take to fill?  Options
A) 15.14mins
B) 16.14mins
C) 17.14mins
D) 18.14mins
E) 19.14mins
1/30+1/20-1/40=7/120   so total time=120/7   =17.14mins   ANSWER:17.14mins
<result>C</result>
if A fills a tank in 30mins,and B fills the same tank in 20mins,and C emptys it in 40min ,if A,B,C works together how much time will the tank take to fill?