Charla wants to cover a certain rectangular area of her driveway with a picture using chalk. If she completes 23 of the area in 12 hour, how long will it take her to complete the entire picture?

If Charla completes 23% of the area in 12 hours, then completing 1% of the area will take 12/23 = <<12/23=0.5217391304347826>>0.52 hours.

Therefore, completing the whole picture will take 0.52 * 100 = <<0.52*100=52>>52 hours. Answer: \boxed{52}.