Miss Wang's loss is: a pair of shoes, 90 yuan+money for customers+money for neighbors (the same as money for customers).

Because Miss Wang borrowed 100 yuan from her neighbor, in addition to the change she gave the customer, there was still money left, so she returned 100 yuan to her neighbor = remaining money+supplementary money.

If a pair of shoes is sold in 60 yuan, the remaining money is100-60 = 40; If a pair of shoes is sold in 30 yuan, the remaining money is 100-30=70.

If there is a special price in 30 yuan, the answer is 170 yuan.

90+( 100-30*2)+( 100-30*2)

That is 90+40+40= 170.

If a pair of 30 yuan discount, the answer is 230 yuan.

90+( 100-30)+( 100-30)

That is 90+70+70=230.

It's simple. You can understand by rehearsing the trading situation of the three of them with ten or one hundred pieces of loose money: you are Miss Wang, and you changed the neighboring store to 100. Looking for a client 40? Look at how much money you have in your hand. Finally, think about how to return the neighboring store 100.