Final answer:
Uncle Smith will receive a total of $270 in simple interest after 3 years.
Step-by-step explanation:
To calculate the total simple interest, we need to calculate the interest on each deposit separately and then add them together. Uncle Smith deposited $2000 at an interest rate of 2.4% per year, so the interest on this deposit after 3 years is $2000 x 0.024 x 3 = $144.
He also deposited $1500 at an interest rate of 2.8% per year, so the interest on this deposit after 3 years is $1500 x 0.028 x 3 = $126.
The total interest he will receive after 3 years is $144 + $126 = $270.