IBPS SO Prelims Exam Model Paper 9

We need to get the efficiencies of A, B and C or the units of work done by them individually.
Statement I:
All three together can finish the work in 7.5 days while C alone takes 20 days to complete the work.
Suppose total work is 60 units (LCM of 7.5 and 20)
⇒ Efficiency of C =

60

20

= 3
⇒ Efficiency of (A + B + C) =

60

7.5

= 8
⇒ Efficiency of (A + B) = 8 – 3 = 5
Efficiency of A can’t be determined.
Combining statement II:
A and B together can finish the work in 12 days.
Efficiency of (A + B) =

60

12

= 5
Efficiency of A can’t be determined.
∴ Both Statements I and II together are not sufficient to answer the question.