Over the past couple of years since I have been teaching the GRE, nearly all the students have shown immense anxiety over the probability questions. Infact probability is the only topic that students go out of their way to study and improve upon – in the process deliberating over irrelevant concepts that are beyond the scope of the new GRE. Last year was a bit different than this year in terms of probability questions. In 2012, more than 90% of my students got to see not more than 1 probability question – usually tested along with other concepts such as Geometry. However this year expect to see 2 to 3 questions from this topic – since January over 45 of my students have seen 2-3 probability questions. However another 20-25 students never saw any probability questions at all. Therefore the number of questions varies but do not expect more than 3 questions from probability.
Number of probability: 0-3 out of 40
Probability questions vary from removing socks from a drawer to tossing coins and dices. Good news is these questions are not very tough and with just some practicing you’ll do fine. Last year I came across several students who mentioned GRE combining probability with geometry. For instance, the probability that a random point will fall within a shaded region of a circle or a triangle. This year was more about merging probability with counting and combination questions – however don’t fret over the possibilities. Just practice a bit more (30-40 questions at maximum) and you should do well.
Here is a practice question that would get you started and allay your probability woes 🙂
Q) A certain jar contains 60 jelly beans—22 white, 18 green, 11 yellow, 5 red, and 4 purple. If a jelly bean is to be chosen at random, what is the probability that the jelly bean will be neither red nor purple?
Since there are 5 red and 4 purple jelly beans in the jar, there are 51 that are neither red nor purple, and the probability of selecting one of these is 51 . Since 60 all of the answer choices are decimals, you must convert the fraction to its decimal equivalent, 0.85. Thus, the correct answer is Choice D, 0.85.
In conclusion I would just say that the probability of getting a probability questions on the GRE is very low 🙂