A can do a certain work in the same time in which B and C together can do it. If A and B together could do it in 10 days and C alone in 50 days,then B alone could do it in :  Pick one.
A) 15 days  B) 20 days  C) 25 days  D) 30 days  E) None of these
Solution   (A +B)’s 1 day’s work =1/50; C's 1 day's work = 1/50   (A+B+C)’s 1 day’s work = (1/10+1/50)=6/50=3/25…..(i)   Also,A’s 1 day’s work =(B +C)’s 1 day’s work ……(ii)   From (i) and (ii),we get : 2 × (A’s 1 day’s work) =3/25   ⇒ A’s 1 day’s work = 3/50   ∴ B’s 1 day’s work = (1/10-3/50)=2/50=1/50   So, B alone could do the work in 25 days.   Answer 25 days
<result>C</result>
A can do a certain work in the same time in which B and C together can do it. If A and B together could do it in 10 days and C alone in 50 days,then B alone could do it in :