What is the rate of simple interest for the first 4 years if the sum of Rs 360 becomes Rs 540 in 9 y...........

Explanation:

Interest for the last 5 years = PTR/100;
= 360*5*6/100 = Rs. 108.
Interest for year = 540-360 = 180;
So, interest for first four years = 180-108 = Rs. 72;
Now, rate for first four years = (72*100)/360*4; = 5%.

Hence, option 4 is the correct answer.