Answer:
28
Step-by-step explanation:
Order the numbers from smallest to largest.
Then cross one out from the left and then the right. Repeat this.
10, 24, 26, 27, 28, 29, 33, 37, 40
24, 26, 27, 28, 29, 33, 37, 40
24, 26, 27, 28, 29, 33, 37
26, 27, 28, 29, 33, 37
26, 27, 28, 29, 33
27, 28, 29, 33
27, 28, 29
28, 29
28