When is the math test?

Fernanda and Andrea completely contradict each other. Likewise for Tatiane and Daniela. Thus Patricia.

Since it said that only one of the 5 girls was completely right and that the others guessed at least one of these information correctly: the month, the day, or the weekday, my solution was simple deduction really, I first scanned the answers these girls came up with starting from which answer was given first, i came up with August 3x September 2x, then i went to the day of the month part which was 16th 2x and 17th 3x, then the weekday which was Monday 3x and Tuesday 2x after that I went with the highest of each answer that was given and ended up with - - - August 17 Monday which was also Patricia's answer

For those who may have gotten confused on what x means in my solution it means times, i was just too lazy to write the actual 5 letter word that many times so ya, laziness

The key bit is that everyone has something right.

So assume it is in September. In that case it must be on the 17th (the only option.) As Andrea and Daniela have both then got the month and date wrong, they must get the day right, yet they cannot, as they are not guessing the same day. Therefore it cannot be in september.

If it is August, then Fernanda and Tatiane have got the month wrong. As they cannot both get the day right (for they are guessing different days) the only thing they can both get right is the date. Therefore it must be the 17th.

As it is not September (therefore it is august) and it is the 17th, the person who is right is Patricia.

If aug16 is a mon/tues, sept 17 will not be either mon or tues. Thus all 4 of these possibilities are incorrect, leaving Patricia as the correct option.