•When the answers of a multiple-choice problem are fairly simple numbers, it may save time to simply substitute each of them into the question until you find the one that works.
–Example: If 3x-3 = 27, find the value of x.
(A) 3
(B) 4
(C) 5
(D) 6
(E) 7
Since the answer choices in this problem increase in value from A to E, you can save some time by starting with answer choice C. Substitute 5 in the given equation.
35-3 = 32 = 9 ≠ 27
So the answer is not choice C. Since the value obtained from choice C (9) is less than the required 27, go to choice D as the next attempt.
36-3 = 33 = 27
Thus, the correct answer is choice D: 6.