Answer:
D. About 24 years
Explanation:
Compounding is the means the future value of an amount saved today while discounting means the present value of a future amount.
In other words, we discount to know the present value of $1 in the future while we compound to know the future worth of $1 saved today.
Let the value of the investment be x. if it is expected to double in n years then using the compound interest formula
fv = pv(1 + r)^n
where fv and pv are the future and present values respectively and n is the time, r is the growth rate
2x = x(1 + 0.03)^n
2 = (1.03)^n
log 2 = log (1.03)^n
= n log 1.03
n = log 2/ log 1.03
n = 23.44
This is approximately 24 years hence option D is right