A man took a loan at rate of 12% per annum simple interest. After 3 years he had to pay 6480 interest. The principal amount borrowed by him was.  Pick
A) rs 14000 B) rs 15000 C) rs 16000 D) rs 18000 E) none of these

Rationale: "explanation : s . i . = p â ˆ — r â ˆ — t / 100 = > p = s . i . â ˆ — 100 / r â ˆ — t = > p = 6480 â ˆ — 100 / 12 â ˆ — 3 = rs 18000 option d"
Answer: D