Three cows work to fill a tub at at different rate. Hose A and B, working together, can fill the tub in 3/5 of an hour. Hoses A and C can fill it in 1/2 an hour. Houses B and C can fill it in 2 hours. How long does it take all 3 cows, working together, to fill the tub? Choose the correct choice from the following answers.
A) 3/10  B) 2/5  C) 6/11  D) 1  E) 6/5
We have ,in 1 hourwhen two hose working together can fill the tub as follow:   1/a + 1/b = 1/3/5 of the work   1/a + 1/c = 1/1/2 of the work   1/b + 1/c = 1/2 of the work   =&gt;Get total both sides we got : 2(1/a +1/b +1/c) = 10+30+15/30 of the work   or 1/a +1/b +1/c = 55/30=11/6 of the work   6/11alculate total amount of time taken when three hoses work together 11/6 = 6/11   6/11
<result>C</result>
Three cows work to fill a tub at at different rate. Hose A and B, working together, can fill the tub in 3/5 of an hour. Hoses A and C can fill it in 1/2 an hour. Houses B and C can fill it in 2 hours. How long does it take all 3 cows, working together, to fill the tub?