Edward was due to make loan payments of $245 today, $410 in two months, and $500 in four months. However, he has agreed instead to make a single equivalent payment $X one month from today. Determine the size of the single equivalent payment $X if the interest rate is 15% p.a. and the agreed focal date is one month from today (Month 1). Answer the following questions, and choose the closest answer from the possible choices following each question:

If the focal date is one month from today, which variable does the payment $245 represent? (Choose from S, P, t, or r)
If the focal date is one month from today, which variable does the payment $410 represent? (Choose from S, P, t, or r)
What value of "t" should you apply to the second loan payment of $410? (Express in 8 decimals)