We would apply the formula for calculating compound interest which is expressed as
A = P(1 + r/n)^nt
where
P represents the initial amount invested
A is the total amount after t years
n is the number of compounding periods in a year
t is the number of years
r is the interest rate
From the information given,
P = 2704
r = 7% = 7/100 = 0.07
n = 3
t = 18
By substituting these values into the formula, we have
A = 2704(1 + 0.07/3)^3 * 18
A = 2704(1.023)^54
A = 9232
The account balance after 18 years is $9232