Assume you are living in a world with 0 inflation rate, 0 risk, and 0 interest rate (no investment opportunity). Your favorite rock band, Metallica, just arrived in your town and you are willing to pay $100 for their concert today. Alternatively, you have to wait a year later when they tour again. You feel that, if you have to wait another day to see the band, your unhappiness will increase, which is equivalent to losing 10 cents to you. How much would you pay for a Metallica's concert a year from now?

Answer is 63.5 but need help with work