Answer: 44
Step-by-step explanation:The way to calculate the number of coins that she had originally is to look at the difference in coins that changed hands. She sold 12 coins, but only bought 7 new ones. 12-7=5. Lucinda now has 5 coins less than what she started out with. So, she has 39 now, and then add 5 and the answer is 44 coins.