# QA – Placement Quizzes | Work and Wages | Question 1

Two friends A and B were employed to do a work. Initial deadline was fixed at 24 days. Both started working together but after 20 days, A left the work and the whole work took 30 days to complete. In how much time can B alone can do the work?**(A)** 40**(B)** 50**(C)** 60**(D)** 70**Answer:** **(C)****Explanation:** Let the total work be 24 units. It is given that A and B together can do the work in 24 days.

=> Combined efficiency of A and B = 24/24 = 1 unit / day

=> Work done in 20 days = 20 units

=> Work left = 24 – 20 = 4 units

Now, this remaining 4 units of work was done by B alone in 10 days.

=> Efficiency of B = 4/10 = 0.4

Therefore, time required by B alone to do the work = 24/0.4 = 60 days

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