She is going to 5 classes 3×5 = 15 and 15÷3=5
Edges that are perpendicular to PR basically means what edges make a 90° angle with PR.
Those edges are HP , RA, TR and QP.
Hence, the answer is A, B and C.
Hi,
Work:
Equation;

Write all numerators above the least common denominator 32.

Calculate the sum of positive numbers.

Simplify (FRACTION RESULT)

Or (DECIMAL RESULT)

Hope this helps.
r3t40