We can start by using the information given to figure out how much battery Maya used in the first 2 hours. If she was left with 38% battery, that means she used 100% - 38% = 62% of her battery. Since 2 hours is 2/24 = 1/12 of a day, we can say that Maya used 62% / 12 = 5.17% of her battery per hour.
Now we can use this rate to figure out how much battery Maya used in the third hour. If she was left with 38% battery after 2 hours, then she had 100% - 38% = 62% of her battery left. If another hour passed by and she was left with 9% battery, that means she used 62% - 9% = 53% of her battery in that hour. Since we know she uses 5.17% of her battery per hour, we can divide 53% by 5.17% to get the total number of hours she spent on her phone:
53% / 5.17% = 10.24 hours
So Maya spent 2 hours + 1 hour + 10.24 hours