Now that you’ve gotten a little more confident, we’re going to give you the opportunity to practice "without the training wheels." When you want to check your work, you can turn to the solutions at the end. If you aren’t familiar with some of the mathematical concepts, make a note to pay particular attention to that chapter in this book; this practice set covers a wide range of topics tested on the GMAT.
On all data sufficiency problems, the answer choices are the same (as you’ve learned). We’ve put them here for your reference.
Ａ. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Ｂ. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
Ｃ. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
Ｄ. EACH statement ALONE is sufficient.
Ｅ. Statements (1) and (2) TOGETHER are NOT sufficient.

A job opening was posted in September and again in January. In September, the number of applicants for the position was 60. What was the percent change in the number of applicants from September to January
(1) The number of applicants in January was one-third the number of applicants in September.
(2) The number of applicants in January was 20.

眼镜有时戴，有时不戴是不是容易加深度数？