Answer:
Robert will have $481 more in his account than Cooper.
Step-by-step explanation:
Compound interest:
The compound interest formula is given by:

Where A(t) is the amount of money after t years, P is the principal(the initial sum of money), r is the interest rate(as a decimal value), n is the number of times that interest is compounded per year and t is the time in years for which the money is invested or borrowed.
Continuous compounding:
Similar to compound interest:

Cooper:
Cooper invested $3,100 in an account paying an interest rate of 2% compounded quarterly. This means that 
After 12 years is A(12). So



Cooper will have $3938.5 in his account.
Robert:
Robert invested $3,100 in an account paying an interest rate of 3 % compounded continuously. So
.
After 12 years.



Robert will have $4419.9 in his account.
How much more money would Robert have in his account than Cooper, to the nearest dollar?
4419.9 - 3938.5 = 481.4
To the nearest dollar, Robert will have $481 more in his account than Cooper.