It is currently 13 Dec 2017, 14:57

# Decision(s) Day!:

CHAT Rooms | Ross R1 | Kellogg R1 | Darden R1 | Tepper R1

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# QOTD #20 The early universe contained only the lightest elements,

Author Message
TAGS:

### Hide Tags

Board of Directors
Joined: 01 Sep 2010
Posts: 3422

Kudos [?]: 9493 [1], given: 1203

QOTD #20 The early universe contained only the lightest elements, [#permalink]

### Show Tags

07 Dec 2017, 09:35
1
KUDOS
Top Contributor
00:00

Difficulty:

45% (medium)

Question Stats:

64% (01:36) correct 36% (01:43) wrong based on 50 sessions

### HideShow timer Statistics

The early universe contained only the lightest elements, hydrogen and helium. Heavier elements, such as carbon, form only in nuclear reactions in stars and are dispersed when the stars explode. A recently discovered gas cloud contained carbon several billion years ago, when the universe was no more than two billion years old.

If the statements above are true, which of the following must, on the basis of them, also be true？

(A)The earliest stars contained only hydrogen.
(B)Some stars were formed before the universe was two billion years old.
(C)The carbon in the gas cloud later formed part of some stars.
(D)No stars identified to date are as old as the gas cloud.
(E)The gas cloud also contained hydrogen and helium.
[Reveal] Spoiler: OA

_________________

Kudos [?]: 9493 [1], given: 1203

Senior CR Moderator
Status: Long way to go!
Joined: 10 Oct 2016
Posts: 1292

Kudos [?]: 1099 [0], given: 62

Location: Viet Nam
Re: QOTD #20 The early universe contained only the lightest elements, [#permalink]

### Show Tags

08 Dec 2017, 06:58
carcass wrote:
The early universe contained only the lightest elements, hydrogen and helium. Heavier elements, such as carbon, form only in nuclear reactions in stars and are dispersed when the stars explode. A recently discovered gas cloud contained carbon several billion years ago, when the universe was no more than two billion years old.

If the statements above are true, which of the following must, on the basis of them, also be true？

(A)The earliest stars contained only hydrogen.
(B)Some stars were formed before the universe was two billion years old.
(C)The carbon in the gas cloud later formed part of some stars.
(D)No stars identified to date are as old as the gas cloud.
(E)The gas cloud also contained hydrogen and helium.

(1) The ealy universe contained no carbon.
(2) Carbons form only from stars when they explode.
(3) A recently discovered gas cloud contained carbon when the universe was about 2b years ago.

From (3), it's clear that there must be carbons when the universe was about 2b years ago.
Then from (2), there must be stars when the universe was about 2b years ago.
Hence, this comes to choice (B).
_________________

Kudos [?]: 1099 [0], given: 62

Director
Joined: 28 Mar 2017
Posts: 690

Kudos [?]: 166 [0], given: 138

Re: QOTD #20 The early universe contained only the lightest elements, [#permalink]

### Show Tags

08 Dec 2017, 09:18
The early universe contained only the lightest elements, hydrogen and helium. Heavier elements, such as carbon, form only in nuclear reactions in stars and are dispersed when the stars explode. A recently discovered gas cloud contained carbon several billion years ago, when the universe was no more than two billion years old.

If the statements above are true, which of the following must, on the basis of them, also be true？

(A)The earliest stars contained only hydrogen. -Stars contained carbon as well. Thus this statement is incorrect.
(B)Some stars were formed before the universe was two billion years old. -Correct
(C)The carbon in the gas cloud later formed part of some stars. -We don't know what happened later
(D)No stars identified to date are as old as the gas cloud. -Out of scope
(E)The gas cloud also contained hydrogen and helium. -We don't know the composition of gas cloud
_________________

Kudos if my post helps!

1. e-GMAT's ALL SC Compilation
2. LSAT RC compilation
3. Actual LSAT CR collection by Broal
4. QOTD RC (Carcass)
5. Challange OG RC

Kudos [?]: 166 [0], given: 138

Re: QOTD #20 The early universe contained only the lightest elements,   [#permalink] 08 Dec 2017, 09:18
Display posts from previous: Sort by