A student was asked to find 4/5 of a number. But the student divided the number by 4/5, thus the student got 18 more than the correct answer. Find the number.  Choose the correct choice from the following choices:  A) 30  B) 35  C) 40  D) 45  E) 50

Rationale: "let the number be x . ( 5 / 4 ) * x = ( 4 / 5 ) * x + 18 25 x = 16 x + 360 9 x = 360 x = 40 the answer is c ."
Answer: C