The principle on which a simple interest of ₹ 55 will be obtained after 9 months at the rate of 3 2/ 3% per annum is

Let. principal = P
Given, SI = 55, Time T = 9 months = 9/12 yr,
Rate R = 3²/₃% = 11/3 %
∴ SI = (P x R x T) / 100
⇒ P = (100 x SI) / (R x T)
⇒ (55 x 100) / [(11 x 9) / (3 x 12)] = 2000
∴ Principal (P) = ₹ 2000