What sum of money lent out at simple interest will amount to ₹ 3400 in 3 yr at 1% per month?

A = ₹ 3400 T = 3 yr , R = 1% per month = 12 % per annum Let the principle be ₹ P.
SI = (PTR/100) = (P x 3 x 12)/100 = ₹ 36P/100
A = (P + SI) = P + 36P/100 = ₹ 136P/100
⇒ 136P/100 = 3400
⇒ P = (3400 x 100)/136 = 2500
∴ Sum = ₹ 2500