Let the marks of the students in class 1 be

the average of these 12 marks is 90, so

which means

similarly, let

be the marks of the students in the second class,
so

which means

The 32 students averaged:
Since there are 2 black sixes and 2 black eights in a typical deck of 52 cards, the probability of choosing one of those 4 out of 52 is 4/52 or 1/13.
B is the correct answer
hope this helps
Answer:
A right triangle
Step-by-step explanation:
All interior angles in a triangle are equal to 180°.
x+x+2x = 180°
4x = 180°
x = 45°
So two of the angles are 45°, and the remaining angle is 45°×2 = 90° (a right angle).