Frank paid very well finance rate of 1.5% on the first $500 and 1% at any amount above $500 how much did he pay at the unpaid balance was $741.23

.015(500) + .01 (241.23)

To calculate how much Frank paid while having an unpaid balance of $741.23, we need to break it down into two parts: the amount up to $500 and the amount above $500.

1. Calculate the amount up to $500:
- The interest rate for this amount is 1.5%.
- Multiply $500 by 1.5% (or 0.015) to find the interest paid:
$500 * 0.015 = $7.50

2. Calculate the interest on the remaining balance above $500:
- The remaining balance is $741.23 - $500 = $241.23.
- The interest rate for this amount is 1%.
- Multiply $241.23 by 1% (or 0.01) to find the interest paid:
$241.23 * 0.01 = $2.41

3. Add the interest from both parts together:
$7.50 + $2.41 = $9.91

Therefore, Frank paid $9.91 while having an unpaid balance of $741.23.