venn diagram

naaga wrote:. All trainees in a certain aviator training program must take both a written test and a flight test. If 70 percent of the trainees passed the written test, and 80 percent of the trainees passed the flight test, what percent of the trainees passed both tests?
(1) 10 percent of the trainees did not pass either test.
(2) 20 percent of the trainees passed only the flight test.


Well, I was not able to use statement 1 to get the answer. So, I will wait for someone to answer that part.

But, statement 2 is sufficient. Using Venn diagram, if 20% passed only flight test, then we know that # of trainees who passed both written & flight tests is = 70%-20% = 50%. Sufficient.

naaga wrote:. All trainees in a certain aviator training program must take both a written test and a flight test. If 70 percent of the trainees passed the written test, and 80 percent of the trainees passed the flight test, what percent of the trainees passed both tests?
(1) 10 percent of the trainees did not pass either test.
(2) 20 percent of the trainees passed only the flight test.


folks I got the answer A but the OA is D, how it satisfies the answer I don't know, help anybody, thanks in advance,