GRE-Quant

GRE Quant Problem Solving
1

First, I would like to know the differences between the following three scenarios.

1. What is the probability that event A or event B occurs?
2. Probability that event A or event B or both occurs?
3. Probability that either event A or event B occurs but not both?

Second, A’s annual salary is 60, B’s annual salary is 80.

  1. A’s annual salary is what percent less than B’s annual salary?
  2. B’s annual salary is what percent greater than A’s annual salary?
2

I]
If there are 2 events, you can have -AB, A0, 0B, 00
1 = 3 = A0, 0B
2 = AB, A0, 0B

II]
% less = \frac{B - A}{B} * 100 = \frac{80-60}{80}*100 = \frac{20}{80}*100 = 25
% more = \frac{B - A}{A} * 100= \frac{80-60}{60}*100 = \frac{20}{60}*100 = 33

The denominator is the quantity being referenced “less than B” - B goes in denominator
“less than A” - A goes in denominator

3

Thank you. Could you elaborate the first question please? I do not understand AB or A0.

Also are you sure about the denominator in the second question?

4

AB = Both A and B occurring
A0 = only A occurring
0B = only B occurring
00 = None
So, in 1 and 3 we have A0 and 0B
Where as in 2, we have A0, 0B as well as AB

Yes, the reference thing works for all % changes questions
Profit %, loss %, % more, % less, % increase, decrease
In all these cases, the value being compared to is always at the bottom