Answer :
Final answer:
The base fare of the old document for an exchange is 426.00 USD, which is the sum of the third and fourth coupon which are being exchanged.
Explanation:
When calculating the base fare of the old document for an exchange with a new ticket, you need to look at the values provided for the old ticket and the new document. The new ticket base fare is given as 150.00 plus additional charges, while the old ticket shows segments with fares of 250.00, 176.00, 176.00, and another 250.00. These values add up to 852.00 for the segments we are exchanging (3rd and 4th coupons; 176.00 from STL to PHX and 250.00 from STL to DCA). This does not include the Q charges and XF fees which are taxes and additional charges, and not part of the base fare. Therefore, the base fare for the old document as per the coupons to be exchanged is 176.00 + 250.00, which is 426.00 USD.