The annual interest rate on the saving account of Xavier which is earned simple interest is 9%.
<h3>What is simple interest?</h3>
Simple interest is the amount charged on the principal amount with a fixed rate of interest for a time period. Simple interest calculated only on the principal amount.
The formula for the simple interest can be given as,
![I=\dfrac{PRT}{100}](https://tex.z-dn.net/?f=I%3D%5Cdfrac%7BPRT%7D%7B100%7D)
Here, (<em>I</em>) is the interest amount on the principal amount of (<em>P</em>) with the rate of (<em>r</em>) in the time period of (<em>t</em>).
Xavier opened a savings account with a deposit of $12,000. At the end of 3 years, the account balance was $12,324.
The principal amount is $12000 and the total amount is $12324. Thus, the interest earned by the Xavier is,
![I=12324-12000\\I=324](https://tex.z-dn.net/?f=I%3D12324-12000%5C%5CI%3D324)
Total time period is 3 years and the account earned simple interest. Thus, put these values in the above formula as,
![324=\dfrac{(12000)R(3)}{100}\\R=\dfrac{32400}{12000\times3}\\R=9\%](https://tex.z-dn.net/?f=324%3D%5Cdfrac%7B%2812000%29R%283%29%7D%7B100%7D%5C%5CR%3D%5Cdfrac%7B32400%7D%7B12000%5Ctimes3%7D%5C%5CR%3D9%5C%25)
Hence, the annual interest rate on the saving account of Xavier which is earned simple interest is 9%.
Learn more about the simple interest here;
brainly.com/question/2294792