1050 divided by 1500=0.7.

Answer: This product can be sold at a minimum discount of 30%, which is 1050 yuan.

135 divided by 75%= 180 (yuan)

135 divided by 125%= 108 (yuan)

180+ 108=273 (yuan)

135*2=270 (yuan)

273-270=3 (yuan)

A: The businessman's income from this transaction is 3 yuan.

4000* 105%=4200 (yuan)

4200 divided by 80%=5250 (yuan)

A: The list price is 5250 yuan.