Wang Yong owes the bank / $8500, 8500. To repay the debt, he paid a fixed amount back to the bank each month. After 2 months, his remaining debt was / $6460

Is the question asking what the payments were? If so, you'll just need to determine how much was paid in total, then divide that if half to determine one payment.

$8500 - $6460 = 2040

$2040 : 2 = $1020 per payment.