ankur.agrawal wrote:Can i post only using the Question no OF OG 12. Saves a lot of time typing

Members won't be able to answer it if they don't have the book handy
So your response time will probably be longer

ankur.agrawal wrote:Can i post only using the Question no OF OG 12. Saves a lot of time typing

OK i will try. But still it is my approach (may not be the correct approach )

Let total work be A.
Let Machine X operating alone fill x part of production lot in 4 hours i.e. work done by machine X is x in 4 hours
Rate of machine X. Rx = (x/4) bottles per hour

Now Machine Y operating alone fill the remaining part of production lot i.e. work done by machine Y is (A-x) in 3 hours.
Rate of machine Y, Ry = (A-x)/3 bottles per hour

We need to know A/Rx or (A/x)4?

(1) Rx = 30 bottles per minute
i.e 1800 bottles per hour. But we don't know the value of A or x. hence INSUFFICIENT

(2) Bottles produced by machine X in 4 hours = Rx * 4 = x bottles
Bottles produced by machine Y in 3 hours = Ry * 3 = (A-x) bottles

Given that x = 2(A-x)
i.e. x = 2A - 2x
i.e. 3x = 2A
i.e A/x = 3/2
Machine X operating alone will fill the entire lot in (A/x)4 hours = (3/2) *4 = 6 hours
SUFFICIENT

CORRECT ANSWER (B)