Firstly, solve the effective annual interest (ieff) with the equation,
ieff = (1 + i/m)^m -1
where i is the interest rate and m is the number of times the interest is compounded in a year. In this problem, m is 12
Substituting the values,
ieff = (1 + 0.034/12)^12 - 1 =0.03453
To solve for the future (F) amount of the present investment (P),
F = P x (1 + ieff)^n
where n is number of years.
F = ($742) x (1 + 0.03453)^15
Thus, the answer is $1234.76.