Explanation:

Let's break it down:

- 8 consecutive even numbers can be written as: x, x+2, x+4, x+6, x+8, x+10, x+12, x+14.

- Their average is given as 17.

- The average formula: (Sum of numbers) / 8 = 17

? (x + x+2 + x+4 + ... + x+14) / 8 = 17

? (8x + (2+4+6+8+10+12+14)) / 8 = 17

The sum inside the bracket = 2+4+6+8+10+12+14 = 56

So, (8x + 56)/8 = 17

? 8x + 56 = 136

? 8x = 80

? x = 10

- The last three numbers: x+10 = 20, x+12 = 22, x+14 = 24.

- Average of these three: (20+22+24)/3 = 66/3 = 22

- Now, average of last three numbers, 36, and 53:

(20 + 22 + 24 + 36 + 53)/5 = 155/5 = 31

- Let's match with options:

1. 31 (Correct, matches our calculation)

2. 32.2 (Incorrect)

3. 31.6 (Incorrect)

4. 29.8 (Incorrect)

Correct answer: Option 1 - 31