Bilquis invested $6,900 in an account paying an interest rate of 5\tfrac{1}{8}5 8 1 ​ % compounded continuously. Sophie invested $6,900 in an account paying an interest rate of 4\tfrac{3}{4}4 4 3 ​ % compounded monthly. After 18 years, how much more money would Bilquis have in her account than Sophie, to the nearest dollar?