Dan took a 20-question multiple-choice test in psycology.

[BTGmoderatorLU]

Source: GMAT Paper Tests

Dan took a 20-question multiple-choice test in psychology. If Dan answered every question, did he answer at least 12 questions correctly?

1) Dan answered fewer than 40 percent of the questions incorrectly.
2) Dan answered at least 25 percent of the questions incorrectly.

The OA is A.

[Jay@ManhattanReview]

Source: GMAT Paper Tests

Dan took a 20-question multiple-choice test in psychology. If Dan answered every question, did he answer at least 12 questions correctly?

1) Dan answered fewer than 40 percent of the questions incorrectly.
2) Dan answered at least 25 percent of the questions incorrectly.

The OA is A.

Let's take each statement one by one.

1) Dan answered fewer than 40 percent of the questions incorrectly.

=> # of incorrect qns < 40% of 20 = 8.
=> # of correct qns > (20 - 8 = 12). Sufficient.

2) Dan answered at least 25 percent of the questions incorrectly.

=> # of incorrect qns > 25% of 20 = 4

Case 1: Say the # of incorrect qns = 5
# of correct qns = 20 - 5 = 15 > 12. The answer is Yes.

Case 2: Say the # of incorrect qns = 10
# of correct qns = 20 - 10 = 10 < 12. The answer is No.

No unique answer. Insufficient.

The correct answer: A

Hope this helps!

-Jay
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