Problem Solving (PS) | Re: Peter invested a certain sum of money in a simple interest bond whose

In 5 years the value went form 300 to 400, a total of $100. This is 20 per year.

In the 3 years early the investment added (3 x 20) = 60 dollars, so it started with 300 - 60 = 240.


20/240 = 1/12 = 8.33%

No need to do the calculation of 1/12. It is non repeating and closer to 10% (1/10) than 5% (1/20)