A fruit seller had some oranges. He sells 20% oranges and still has 400 oranges. How many oranges he had originally?
Answers
A) 420
B) 700
C) 220
D) 500
E) none of these

Rationale: "explanation : he sells 20 % of oranges and still there are 400 oranges remaining = > 80 % of oranges = 400 ⇒ ( 80 × total oranges ) / 100 = 400 ⇒ total oranges / 100 = 5 ⇒ total oranges = 5 × 100 = 500 answer : option d"
Answer: D