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 Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

A cube with its sides numbered 1 through 6 is rolled twice [#permalink]
28 Apr 2012, 05:33

1

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

35% (medium)

Question Stats:

58% (02:36) correct
42% (01:49) wrong based on 64 sessions

A cube with its sides numbered 1 through 6 is rolled twice, first landing on a and then landing on b. If any roll of the cube yields an equal chance of landing on any of the numbers 1 through 6, what is the probability that a + b is prime?

(A) 0 (B) 1/12 (C) 5/12 (D) 7/18 (E) 4/9

I am not sure if the OA is correct. Thanks for help !

Re: A cube with its sides numbered 1 through 6 is rolled twice [#permalink]
28 Apr 2012, 05:50

Expert's post

qtrip wrote:

A cube with its sides numbered 1 through 6 is rolled twice, first landing on a and then landing on b. If any roll of the cube yields an equal chance of landing on any of the numbers 1 through 6, what is the probability that a + b is prime?

(A) 0 (B) 1/12 (C) 5/12 (D) 7/18 (E) 4/9

I am not sure if the OA is correct. Thanks for help !

Re: A cube with its sides numbered 1 through 6 is rolled twice [#permalink]
13 Apr 2014, 01:13

Bunuel wrote:

qtrip wrote:

A cube with its sides numbered 1 through 6 is rolled twice, first landing on a and then landing on b. If any roll of the cube yields an equal chance of landing on any of the numbers 1 through 6, what is the probability that a + b is prime?

(A) 0 (B) 1/12 (C) 5/12 (D) 7/18 (E) 4/9

I am not sure if the OA is correct. Thanks for help !

The question says "first landing on a and then landing on b" so I assumed that the result in both rolls of the dice had to be different, so I didn't count 1,1. So for me answer was D. Was my assumption wrong?

Re: A cube with its sides numbered 1 through 6 is rolled twice [#permalink]
13 Apr 2014, 01:21

NAL9 wrote:

Bunuel wrote:

qtrip wrote:

A cube with its sides numbered 1 through 6 is rolled twice, first landing on a and then landing on b. If any roll of the cube yields an equal chance of landing on any of the numbers 1 through 6, what is the probability that a + b is prime?

(A) 0 (B) 1/12 (C) 5/12 (D) 7/18 (E) 4/9

I am not sure if the OA is correct. Thanks for help !

The question says "first landing on a and then landing on b" so I assumed that the result in both rolls of the dice had to be different, so I didn't count 1,1. So for me answer was D. Was my assumption wrong?

Question says the roll landed on a and b, a and b can be different or same. The question does not give any idea about that, so assuming they are different is not correct in my opinion.

Re: A cube with its sides numbered 1 through 6 is rolled twice [#permalink]
13 Apr 2014, 05:27

Expert's post

NAL9 wrote:

Bunuel wrote:

qtrip wrote:

A cube with its sides numbered 1 through 6 is rolled twice, first landing on a and then landing on b. If any roll of the cube yields an equal chance of landing on any of the numbers 1 through 6, what is the probability that a + b is prime?

(A) 0 (B) 1/12 (C) 5/12 (D) 7/18 (E) 4/9

I am not sure if the OA is correct. Thanks for help !

The question says "first landing on a and then landing on b" so I assumed that the result in both rolls of the dice had to be different, so I didn't count 1,1. So for me answer was D. Was my assumption wrong?

Unless it is explicitly stated otherwise, different variables CAN represent the same number. _________________