AIM TO CRACK GMAT wrote:A 6 sided dice is thrown 3 times. What is the probabilty that the sum of the throws is less than 6?
A) 1/18
B)5/108
c) 5/27
d)1/27
Although it's palpably NOT an original GMAT problem, yet it deserves a shot by GMATians.
When 3 dice are thrown, total outcomes are (6)(6)(6) = 216.
For the sum to be less than 6, we've only three possible sums to accept and those are 3, 4, or 5.
A sum of 3 can be had in just one way, and i.e. 1 1 1.
A sum of 4 can be had in just three ways, and those are 1 1 2, 1 2 1, and 2 1 1.
A sum of 5 can be had in just six ways, and those are 1 1 3, 1 3 1, 3 1 1, 1 2 2, 2 1 2, and 2 2 1.
Thus the favorable number of outcomes = 1 + 3 + 6 = 10.
Hence, the required probability = [spoiler]
10/216 = 5/108.
Pick B[/spoiler]
The mind is everything. What you think you become. -Lord Buddha
Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001
www.manyagroup.com
