perseverant wrote:

Fred has greater lung capacity than George. Since Harold has greater lung capacity than Joe, it follows that Fred must have greater lung capacity than Joe.

Any of the following, if introduced into the argument as an additional premise, makes the argument logically correct EXCEPT:

a)Fred has greater lung capacity than Harold.

b)George has greater lung capacity than Harold.

c)Fred and Harold have the same lung capacity.

d)Harold has greater lung capacity than George.

e)George and Harold have the same lung capacity.

Could someone explain in detail the best way to tackle this kind of question? I came across this type of question twice and gor it wrong both times.

Thanks!

Let's use some maths here..

Let the respective capacities of Fred,George, Harold, Joe be F,G,H and J

Given: F > G, and H > J

To prove : F > J

As per the argument we have 4 options, which can prove F > J.

Option 1:

F > H, but given: H > J , so F > J

Option 2:

G > H, but given F > G and H > J ...So F > G and G > H and H > J....so F > J

Option 3:

F = H, but given H > J...So F > J

Option 4:

ANSWERH > G... But we don't know what is the relation of H and F... So We CAN'T prove that F > J

Option 5:

G = H, but given that F > G, so F > H, but H > J...so F > J

Hope it helps..revert if not clear