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

### Instruction:
What are the miles when the Carvill Hurricane Index (CHI) is equal to 9.9?

### Inputs:
table_name: table, columns: ['Name', 'Year', 'Landfall', 'NHC Advisory Number', 'V(mph)', 'R(miles)', 'Saffir-Simpson Category', 'CHI']

### Response:
SELECT R(miles) FROM table WHERE CHI = 9.9