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 140?
Choose the most appropriate option:  A) 28  B) 29  C) 30  D) 31  E) 32

Rationale: "let x be the number of students in the largest class . then x + ( x - 2 ) + ( x - 4 ) + ( x - 6 ) + ( x - 8 ) = 140 5 x - 20 = 140 5 x = 160 x = 32 the answer is e ."
Answer: E