Math GRE 2

Set A: {1, 3, 4, 6, 9, 12, 15} If three numbers are randomly selected from set A without replacement, what is the probability that the sum of the three numbers is divisible by 3?

= 5C3/7C3

In 2008, the total revenue from movies was 842.1 million dollars. If Rocky XII generated 4.2 million dollars in revenue, approximately what percent of the total revenue was generated by Rocky XII?

Divide the top and the bottom by 8. And to do so, we got 100 at the denominator

How many three-digit numbers are there such that all three digits are different and the first digit is not zero?

First digit : 9 Second digit : 9 Third digit : 8

List A: {x, x, x, y, y, y, 3x+y, x-y } If the median of list A is 10 and 0 < x < y, what is the range of list A?

We need t know the largest number and smallest number of the set. SO our first step is to arrange from smallest to largest. x - y), x, x, x, y, y, y, (3x + y) range = 3X+ Y - X+y = 2(X+Y) Median = (X+Y)/2 = 10 range = 40