the continuous compounding formula is

A = Pe^(rt)

P = $1700 is principal or present value

A = 2P = $3400 is future value or maturity value

r = 0.016 or 1.6% annual interest rate

e = 2.71828 Napier's constant

t = ? number of years

3400 = 1700 e^(0.016t) divide both sides by 1700

e^(0.016t) = 2 use ln function on both sides

0.016t ln e = ln 2

t = ln2/0.016

t = 43.32 years

after 43.42 years the initial investment will double.