1 Answers
Option 3 : 25%
As not mentioned we assume that interest is compounded annually so n = 1.
After 2 years,
S.I. = prt = 2pr
C.I. = p(1 + r/n)nt – p = p(1 + r)2 – p = p(2r + r2)
C.I. – S.I. = pr2
After 3 years,
S.I. = prt = 3pr
C.I. = p(1 + r / n)nt – p = p(1 + r)3 – p = p(r3 + 3r2 + 3r)
C.I. – S.I. = p(r3 + 3r2)
Ratio = r2 / (r3 + 3r2) = 4 / 13
⇒ 13r2 = 4r3 + 12r2
⇒ r2 = 4r3
⇒ r = 1 / 4 = 25%
∴ rate of interest is 25%.
4 views
Answered