simple interest on a sum of money is 1/3rd of the sum itself and the number of years is thrice the rate percent. find the rate of interest.

Question

question about simple interest.

Answer 1

The formula for simple interest is I = Prt, where I is interest amount, P is the starting principle, r is the decimal equivalent interest rate, and t is the time in years.  For this problem, it is given that I = 1/3 P and t = 3 (100)r.  Plugging the equivalent values into the equation yields:

 

1/3 P = P (r) (300r)  -->  1/3 = 300r²  -->  r² = 1/900  -->  r = 1/30 = .03333  or 3.33%