1. Analysis: The first payment 120 yuan is not within the scope of preferential treatment, so there is no need to add preferential payment.

I paid 432 yuan for the second time, which is within the preferential range. If the question means full-price 10%, then

120+432/0.9=600 yuan

2. Analysis: 20% off the original amount payable to 600 yuan, 500 yuan or above 100 yuan; 10% off the remaining 500.

500/0.9+ 100*0.8=530 yuan.

120+432-530=22 yuan

There is no discount for this person to buy it twice. * * * 600 yuan.