The simple interest on a sum of money is 4/9 of the principal. Find the rate percent and time, if both are numerically equal.
6 years 2 months
6 years 5 months
6 years 8 months
None of these
Explanation:
Let sum = Rs. x Then, S.I. = Rs. 4x/9
Let rate = R% and time = R years.
Then, [x $\times$ R $\times$ R / 100] = 4x / 9 or $R^2$ = 400/9 or R = 20/3 = 6 2/3
Rate = 6 2/3 % and Time = 6 2/3 yrs. = 6 yrs. 8 months.