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

### Instruction:
How many Liquidat (c) have a purpose of dual (machine & hand composition)?

### Inputs:
table_name: table, columns: ['Sn/Sb (%)', 'Liquidat (°C)', 'Solidat (°C)', 'Hardness ( Brinell )', 'Purpose']

### Response:
SELECT COUNT Liquidat (°C) FROM table WHERE Purpose = dual (machine & hand composition)