SI=160
TIME=2 YEAR
CI=164
So,
SI= PRT/100
160=PR*2/100
PR=8000...........(i equation)
NEXT
CI=P(1+R/100)^2-P
TAKE P COMMON
164=P((1+R/100)^2-1)........(ii equation)
Divide first equation by second equation
8000/164=(PR)/P((1+R/100)^2-1)
2000/41=R/(1+R/100)^2-1
CROSS MULTIPLICATION
2000*{(1+R/100)^2-1}= 41R
Open bracket
2000*(1+R^2/10000+2R/100-1)=41R
Gives
2000*(R^2/10000+2R/100)=41R
(R^2)/5+40R= 41R
Cancel one R
(R/5)+40=41
R/5=41-40
R/5=1
R=5%
Ans RATE = 5%