Answer: 2(12+8) +3
Step-by-step explanation: In the morning they made 12 + 8 airplanes = (12 + 8)
In the afternoon they doubled the number that they made in the morning = 2 (12 + 8)
Finally, you would add 3 to this for the ones that her brother made = 2 (12 + 8) + 3