Answer: 20.86%
Explanation: From the question, the credit term is 2/10, n/45. Which means that the customer gets a 2% discount if payment is made within 10 days. But the customer did not make use of this offer. The equivalent annual Interest lost on the amount of purchases is :
365/ (45-10) * 0.02 = 365/35*2%
= 0.20857 *100= 20.86%
This is calculated using 365 days in a year.