2/10, n30 means:

a. the supplier will pay a discount of from 2-10% if paid within thirty days

b. if the customer pays within 30 days from the date of purchase, they get a 2% rebate, payable in 10 days

c. if the customer pays within ten days from the date of invoice, they get a 2% discount, otherwise the full amount is due in 30 days from the invoice date

d. the customer gets a 10% discount if paid within two days from the date of purchase