How do you figure percentages problems without calculations?

How do you figure percentages problems? If you encounter a math percentage question on SAT test which you don’t know how to solve it, read the problem carefully, eliminate choices which seem to be illogical and make guess from among the remaining answer choices. In fact, you try to figure out percentages problems without involving calculations. Now we illustrate how this SAT MATH Strategy works.

Example

A box contains some black and white stones. The ratio of the number of black to white stones is 5:7. What percent of stones are white?

(A) 8.33%
(B) 14%
(C) 20%
(D) 40%
(E) 58.33%

How do you figure percentages problems | Give a new direction to your thinking

Observe in above percentages problem that there are 7 white stones for every 5 black stones. It means that number of white stones is greater than the black ones. So percent of white stones must be greater than the percent of black stones. It is possible only when white stones are more than 50 percent. So any answer choice that is below 50 percent is wrong choice. Therefore, eliminate all answer choices (A), (B), (C) and (D) which are less than 50%. Remaining choice (E) must be the answer.