A student was asked to find 4/5 of a number. But the student divided the number by 4/5, thus the student got 45 more than the correct answer. Find the number. Choose the correct choice from the following answers
A) 60
B) 80
C) 100
D) 120
E) 140

Rationale: "let the number be x . ( 5 / 4 ) * x = ( 4 / 5 ) * x + 45 25 x = 16 x + 900 9 x = 900 x = 100 the answer is c ."
Answer: C