The standard quantity of metal per ring is 0.57 kilograms.
Explanation:
Each ring requires 0.52 kilograms of a special metal.
The allowance for waste is 0.03 kilograms per ring, while the allowance for rejects is 0.02 kilograms per ring.
So, the standard quantity of metal per ring = 0.52 kg of metal required + 0.03 kg of allowance for waste + 0.02 kg of allowance for rejects)
=
kilograms.
Hence, the standard quantity of metal per ring is 0.57 kilograms.