Critical Reasoning

Planetary bodies differ from one another in their composition, but most of those in the Solar System have solid surfaces. Unless the core of such a planetary body generates enough heat to cause volcanic action, the surface of the body will not be renewed for millions of years. Any planetary body with a solid surface whose surface is not renewed for millions of years becomes heavily pockmarked by meteorite craters, just like the Earth's Moon. Some old planetary bodies in the Solar System, such as Europa, a very cold moon belonging to Jupiter, have solid icy surfaces with very few meteorite craters.

If the claims above are true, which one of the following must, on the basis of them, be true?

(A) The Earth's Moon does not have an icy surface.
(B) If a planetary body does not have a heavily pockmarked surface, its core does not generate enough heat to cause volcanic action.
(C) Some planetary bodies whose cores generate enough heat to cause volcanic action do not have solid icy surfaces.
(D) Some of Jupiter's moons are heavily pockmarked by meteorite craters.
(E) Some very cold planetary bodies have cores that generate enough heat to cause volcanic action.

OA Later

IMO E

Surface not renewed -> heavily pockmarked

Not heavily pockmarked -> surface renewed.

surface renewed -> volcanic action

IMO it's 'B'.

paddle_sweep wrote:IMO it's 'B'.

Pick E.

Paddle sweep here is why u missed it : Pattern followed : If X then Y; if Y then Z. So if No Z, then No Y.

But Option B construes that If No Z , then No X

X : Heat generation

Y : renewal

Z: Crater formation by heavily pockmarked surface.

whereas in E, it must be true becox in Europa, the surface is renewed. How it is renewed? It is renewed by the heat generated by volcanic action. So how is heat generated?? It means they have CORES to generate heat that inturn causes volcanic action which inturn renew the surface which inturn makes the planetary bodies to have few craters.

Pick E.

Hi all,

thank you for the question Sudhanshu.

We have following argument:

Premise 1:

Unless the core of such a planetary body generates enough heat to cause volcanic action, the surface of the body will not be renewed for millions of years.

if not x, not y
Premise 2:

Any planetary body with a solid surface whose surface is not renewed for millions of years becomes heavily pockmarked by meteorite craters, just like the Earth's Moon.

Any planetary body with a solid surface not y becomes z
Premise 3:

Some old planetary bodies in the Solar System, such as Europa, a very cold moon belonging to Jupiter, have solid icy surfaces with very few meteorite craters.

Case Europa - planetary body with a solid surface - not z

If the claims above are true, which one of the following must, on the basis of them, be true?

We are looking for conclusion of deductively valid argument

Answer E:

Some very cold planetary bodies have cores that generate enough heat to cause volcanic action.

Look at premises 3, 2, 1.
if not x, not y
y
------
so x

Answer E denies the consequent of premise 1 and makes the whole argument valid. I choose answer E.


Best,
Maciek

OA is E guys. I picked B. Stupid I am