A company's accounts department discovered that some of the cheques issued to suppliers have been fraudulently altered, resulting in a total loss of $120,000 to the company. During the investigation, it was found that the fraud had been carried out by an employee who had altered a total of 15 cheques over the course of six months. The employee altered the payee name, the amount and the signature of the cheques to divert the funds to their personal account. The company wants to calculate the average amount per cheque that had been fraudulently altered by the employee.

The investigation revealed that the total amount of funds that had been diverted to the employee's personal account was $120,000. The employee had altered the cheques as follows:

• Cheques 1-5: $8,000 each
• Cheques 6-10: $12,000 each
• Cheques 11-15: $16,000 each

Assuming that the average amount per cheque is the same for all 15 cheques, determine the average amount per cheque that had been fraudulently altered by the employee.

(Show all calculations and round to the nearest cent.)