A certain sum is lent for 3yrs at 10 compound interest p a if the C I for the 3rd year is 242 Then w...........

Explanation:

R – 10% = 1/10 ….. (10)³ = 1000, let P=1000
.                      1000
100……………..100…………….100
.                       10……………….10
.                                              10
.                                                1
C.I for 3rd yr = 121
121 = 242
1 = 2
P = 1000 = 2000
S.I = 4*10 = 40% of 2000 = rs800

Hence, option 2 is the correct answer.