In a school with 5 classes, each class has 2 students less than the previous class. How many students are there in the largest class if the total number of students at school is 115?  Choose the correct choice from the following
A) 25  B) 26  C) 27  D) 28  E) 29

Rationale: "let x be the number of students in the largest class . then x + ( x - 2 ) + ( x - 4 ) + ( x - 6 ) + ( x - 8 ) = 115 5 x - 20 = 115 5 x = 135 x = 27 the answer is c ."
Answer: C