It is the beginning of September and you have been offered the following deal to go​ heli-skiing. If you pick the first week in January and pay for your vacation​ now, you can get a week of​ heli-skiing for . ​However, if you cannot ski because the helicopters cannot fly due to bad​ weather, there is no​ snow, or you get​ sick, you do not get a refund. There is a probability that you will not be able to ski. If you wait until the last minute and go only if you know that the conditions are perfect and you are​ well, the vacation will cost you . You estimate that the pleasure you get from​ heli-skiing is worth per week to you​ (if you had to pay more than​ that, you would choose not to​ go). If your cost of capital is per​ year, should you book ahead or​ wait?