What is the principal, if after five years at 11% p.a. simple interest, it amounts to rs 18600?

Let Principal=1,
SI =PRT%.
So, SI = 1 ×11/100×5
SI = 11/20.
And Principal(P)=1.
Amount=P+SI,
Amount=1+11/20,
Amount=31/20 which is equal to 18,600.
So the value of 1 ratio will be12,000.
So, the principal will be 12,000 and the interest will be 6,600 (11/20×12,000).
So the answer will be Rs.12,000(Principal).