How many pairs of triangles appear congruent? he triangles may overlap

There are 4 pairs of overlapping triangles that I can see that are congruent. Two pairs share vertically opposite angles.
One more pair have right angles at the bottom of the rectangle. 
One other pair have right angles at the top of the rectangle. 

Look, when you want to do something like put it like x^2. x2 could mean x² or x₂. so to clear confusion, know the notation. to find the product multiply the x's and you get -8x and the y's and you get 6y. since it's all being multiplied it is just -8x6y, or answer a. although the better answer is -48xy(combining -8 and 6) because you should multiply constants whenever you can.

1/125 probability for each student so, a 0.8 percent probably of winning per student.