A is twice efficient than B. If together they can finish the work in 15 days, then in how many days will B alone finish the work?

40 45 50 35

45

A         :        B Efficiency =     2         :        1 Total work  ⇒ Efficiency of (A+B) × Time = (2+1) × 15 ⇒ 45 unit Time taken by B ⇒ \(\frac{Total\;Work}{Efficiency}\) = \(\frac{45}{1}\) ⇒ 45 days