Penny's tree grows 3 % of its original height each month. If the tree was 10 feet tall when she planted it, how tall will it be after one year?

If it grows by 3% per month, then we need to multiply the height by 1.03 each month ...03 = 3%

Month 1: 10 X 1.03 = 10.3

Month 2: 10.3 X 1.03 = 10.609

Month 3: 10.609 X 1.03 = 10.9273

Month 4: 10.9273 X 1.03 = 11.2551

Month 5: 11.251 X 1.03 = 11.5928

Month 6: 11.5928 X 1.03 = 11.9406

Month 7: 11.9406 X 1.03 = 12.2988

Month 8: 12.2988 X 1.03 = 12.6678

Month 9: 12.6678 X 1.03 = 13.0478

Month 10: 13.0478 X 1.03 = 13.4292

Month 11: 13.4392 X 1.03 = 13.8424

Month 12: 13.8424 X 1.03 = 14.2577

So, the answer is 14.2577 feet tall.