The credit terms 11/12, n/30 are interpreted as: 30% discount if paid within 11 days 12% cash discount if the amount is paid within 11 days, with balance due in 30 days. 11% cash discount if the amount is paid within 12 days, with the balance due in 30 days. 30% discount if paid within 12 days. 11% discount if paid within 30 days. Answer is 11% cash discount if the amount is paid within 12 days, with the balance due in 30 days.

The credit terms 11/12, n/30 are interpreted as:

      30% discount if paid within 11 days
      12% cash discount if the amount is paid within 11 days, with balance due in 30 days.
      11% cash discount if the amount is paid within 12 days, with the balance due in 30 days.
      30% discount if paid within 12 days.
      11% discount if paid within 30 days.
Answer is
11% cash discount if the amount is paid within 12 days, with the balance due in 30 days.