IBPS Clerk Mains 2019 Paper

(a) Quantity A :
Let total units of work = 120 units (LCM of 12, 15and 24)
⇒ Efficiency of P and Q together =

120

12

=10
⇒Efficiency of Q and R together =

120

15

=8
⇒ Efficiency of R and P together =

120

24

=5
⇒ Efficiency of P, Q and R together =

(10+8+5)

2

=

23

2

days
⇒ Efficiency of Q =

23

2

−5=

13

2

⇒ Time taken by Q to finish the work alone =

120×2

13

days
=

240

13

days
Quantity B :
Let total units of work = 30 units (LCM of 10 and 15)
⇒ Efficiency of S =

30

10

=3
⇒ Efficiency of T =

60

15

=2
Since S left after 5 days.
Unit of work left after 5 days = 30–5×(3+2)=5 units
⇒ Time taken by T to finish the remaining work
=

5

2

=2.5 days
⇒ Total time to finish the whole work = 5 + 2.5 days
= 7.5 days
∴ Quantity A > Quantity B