alloys!!

[tpw536w]

can anyone please help me with this question? In parts per 1000, what is the maximum number of alloys that can be added to platinum?

[heathfield]

You don't say if it's for jewellery, but if so, you can find out about permitted amounts here.
If you mean for products generally, well, there are alloys that contain next to none, and where the platinum is regarded as an acceptable 'contamination' that doesn't do any harm.

[misswright]

Platinum jewellery is usually 950 parts platinum, 50 alloy.