Mrs. Diaz needs a new whiteboard for her classroom. She can buy it from Office Supply for $49.99 with a 15% teacher discount, or from Office Wholesale for $47.99 with a $10 rebate. Find the final price that Mrs. Diaz has to pay for the whiteboard after the better incentive is applied. Round the answer to two decimal places.
The teacher discount at Office Supply is equal to $49.99 * 0.15 = $7.50.
After the discount, Mrs. Diaz would pay $49.99 - $7.50 = $42.49 at Office Supply.
After the rebate, Mrs. Diaz would pay $47.99 - $10 = $37.99 at Office Wholesale.
Hence, Mrs. Diaz should buy the whiteboard from Office Wholesale, and she will have to pay $37.99. Answer: \boxed{37.99}.