Scheduled payments of $$1400$ due today and $$1600$ due with interest at $11\mathrm{.}5\%$ compounded annually in five years are to be replaced by two equal payments. The first replacement payment is due in $18$ months and the second payment is due in $4$ years. Determine the size of the two replacement payments if interest is $11\%$ compounded quarterly and the focal date is $18$ months from now.

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