The Simple Interest on a certain sum of money for two years is Rs. 40 ...
SI for 2 years=40
THUS,SI for 1 year=40/2=20
As for the first year CI and SI are always same so,
CI for first year=20
give that CI for 2 years is 40.5;
So CI for second year =40.5-20=20.5
Difference in CI for two successive years=20.5-20=0.5
so;
0.5 is the interest for one year on the interest of first year,that is,on rupees 20;
thus,
rate=(100*I)/(P*T)
=(100*0.5)/(20*1)
=2.5 percent
therefore; the rate is 2.5 % per annum
P = (100*I)/(R*T)
= (100*40)/(2.5*2)
= 4000/5
= 800 , i.e. , (b)
The Simple Interest on a certain sum of money for two years is Rs. 40 ...
Given, Simple Interest (SI) for 2 years = Rs. 40
Compound Interest (CI) for 2 years = Rs. 40.50
Let the principal be x and rate be r.
As we know, SI = (P * R * T)/100
Substituting the given values, we get, 40 = (x * r * 2)/100
=> 2rx = 400
Similarly, we know, CI = P[(1 + (R/100))^T - 1]
Substituting the given values, we get, 40.50 = x[(1 + r/100)^2 - 1]
=> x[(1 + r/100)^2] = 40.50 + x
Now, we can substitute 2rx = 400 in the second equation and simplify it to get x = Rs. 800.
Therefore, the sum of money is Rs. 800 (Option B).