We have an investment that is compounded semi-anually.
The equation for the future value of an compounded interest investment is:

where:
FV is the future value.
PV is the present or initial value of the investment (PV=100).
r is the annual nominal interest rate (r=5.5%=0.055).
m is the number of capitalization subperiods in the year. In this case, as it is semiannually, m=12/6=2.
n is the number of yearly periods that the investment last (n=6 years).
Then, we can replace the variables with the values and calculate:

Answer: the value of the investment after 6 years is $138.48.