Hello! So, one account earns 3.4% simple interest, and the other one earns ½ of that annual interest, which is 1.7%, because 3.4/2 is 1.7. The formula for finding simple interest is prt, with p being the principal (initial amount), r being the rate (simple interest rate), and t being time (could be in months or years). In this case $500 is the principal for both amounts. The first account earns 3.4% interest and the second account earns 1.7% interest. We are talking about both of them being earned over 4 years. If you multiply correctly, here are your answers:
First account: $68
Second account: $34
Now, let's add the amounts of interest. 68 + 34 is 102. There. Gia will earn $102 in interest in 4 years. The answer is D: $102.
Note: When it comes to the formula prt, you multiply all of the amounts. Plus, you can convert the percents into decimal form. In this case 3.4% is 0.034 and 1.7% is 0.017. You can multiply that number by the principal and the time to get the same answer as above.
