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:

What periodic interest rate should you apply to the third loan payment of $500? (Express in 8 decimals)
How many focal date equivalent values do you need to determine before solving for $X?
Your answer for $X at the focal date is . (Carry all the decimals in the computation until completion, then round the final answer to two decimal places)