Below is an instruction that describes a task. Write a response that appropriately completes the request in English. Please answer in English.

### Instruction:
A candy store uses food colouring in various candies. Each lollipop uses 5ml of food colouring, and each hard candy also needs food colouring. In one day, the candy store makes 100 lollipops and 5 hard candies. They do not use food colouring in anything else. The store has used 600ml of food colouring by the end of the day. How much food colouring, in millilitres, does each hard candy need?

### Response:
In total, the lollipops needed 100 lollipops * 5ml of food colouring per lollipop = <<100*5=500>>500ml of food colouring.
This means that the hard candies needed 600ml total food colouring used – 500 ml food colouring used for lollipops = 100ml of food colouring.
As there were 5 hard candies, this means that each hard candy needed 100ml of food colouring needed for hard candies / 5 hard candies = <<100/5=20>>20 ml of food colouring.
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