What sum (in ₹) will earn a simple interest of ₹480 in 3 years at 20% per year rate of interest?

Correct option is B

SI = (P × R × T) / 100 480 = (P × 20 × 3) / 100 ⇒ P = (480 × 100) / (20 × 3) = 48000 / 60 = ₹800
Explanation of options: (a) ✘ ₹400 earns only ₹240 interest in 3 years at 20% (b) ✔ ₹800 earns ₹480 interest at 20% for 3 years (c) ✘ ₹1600 earns more interest than ₹480 (d) ✘ ₹1200 gives ₹720 — too high