Final answer:
Rodney's investment is worth approximately $2,503.57 in one year.
Step-by-step explanation:
To calculate Rodney's investment worth in one year, we can use the formula for compound interest:

Where:
A = the future value of the investment
P = the principal amount (initial investment)
r = the annual interest rate (in decimal form)
n = the number of times the interest is compounded per year
t = the number of years
In this case, Rodney invests $2,400 today at an APR of 4.23%, compounded monthly. Therefore:
P = $2,400
r = 4.23% = 0.0423
n = 12 (compounded monthly)
t = 1 year
Substituting these values into the formula, we get:

Calculating this expression gives us the final value of Rodney's investment after one year, which is approximately $2,503.57.