Solution -
Given,
Principal = P
Amount = 3P (triples itself)
S.I = Amount - Principal
S.I = 3P - P
S.I = 2P
T = 15
R = r
S.I = (P×R×T) / 100
2P = (P × r × 15) / 100
200P = (P × r × 15)
r = 200/15
r = (40/3)%
Therefore,
The value of r is (40/3)%.
Hence,
The correct answer is option (b) (40/3)%.
Thank You