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

### Instruction:
What is the average SFC in lb/(lbf·h) for engines with an Effective exhaust velocity (m/s) larger than 29,553, and a SFC in g/(kN·s) of 17.1?

### Inputs:
table_name: table, columns: ['Engine type', 'Scenario', 'SFC in lb/(lbf·h)', 'SFC in g/(kN·s)', 'Specific impulse (s)', 'Effective exhaust velocity (m/s)']

### Response:
SELECT AVG SFC in lb/(lbf·h) FROM table WHERE Effective exhaust velocity (m/s) > 29,553 AND SFC in g/(kN·s) = 17.1