In 1990 a total of x earthquakes occurred worldwide, some but not all

Hi NYCgirl15,

You can treat this question 'conceptually', using variables and logic to get to the answer. You can also TEST VALUES to get to the solution.

We're given a couple of facts to work with:
1) There were a total of X earthquakes
2) Of those earthquakes, M of them occurred in Asia

We're asked for the ratio of the number of earthquakes that occurred IN ASIA to the number of earthquakes that DID NOT occur in Asia.

Let's TEST VALUES
X = 5 total earthquakes
M = 2 occurred in Asia

Thus, there were 3 earthquakes that DID NOT occur in Asia....

The answer to the question is 2:3
We just need to plug in the values for X and M and find the match...

Answer A: X/M = 5/2 NOT a match
Answer B: M/X = 2/5 NOT a match
Answer C: M/(X-M) = 2/(5-2) = 2/3 This IS a match
Answer D: X/(X-M) = 5/(5-2) = 5/3 NOT a match
Answer E: 1 - (M/X) = 1-2/5 = 3/5 NOT a match

Final Answer:

GMAT assassins aren't born, they're made,
Rich