Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What is the average Grid for the honda cbr1000rr, with 18 laps and a time of +1:12.884?

### Inputs:
table_name: table, columns: ['Rider', 'Bike', 'Laps', 'Time', 'Grid']

### Response:
SELECT AVG Grid FROM table WHERE Bike = honda cbr1000rr AND Laps = 18 AND Time = +1:12.884