If a sum of Rs216 becomes 343 in 3yrs Then find C I on Rs43 200 in 3yrs at the same rate of interest...........

Explanation:

first we will find rate of interest
Note : – root varies according to time, here Time is 3 yrs so
(216)^1/3 : (343)^1/3
6 : 7 – difference is 1. Now 1/6*100 = 16(2/3)%
Now according to question C.I for 3 yrs
16(2/3)% = 1/6 .         6 …………7
.                        .       6 …………7
.                        .       6 …………7
216 − 343 = 127
216 =43,200
1 = 200
127 = 25,400  

Hence, option 4 is the correct answer.