Answer:
Arbitrage opportunity may exists as the ZCBs selling at different price at same time due to change in their YTM .
The PV of 100 face value zcb with different ytm are different , in this case.
for one year maturity with face value 100 current price = fv/ pv at 8% = 92.59
for Two year maturity with face value 100 current price = fv / Pv at 9% for two years = 84.167 , if the bond holder sell the bond after 1 year only, the price = 91.74 .
a) The arbitrage opportunity exist with buy two bond with face value 100 with maturity of 1 year and face value 110 with maturity of 2 years.
b) profit 0.01 , as difference between PV of both bond at their YTM rate.