Martha bought an armchair and a coffee table at an auction and sold both items at her store. Her gross profit from the purchase and sale of the armchair was what percent greater than her gross profit from the purchase and sale of the coffee table?
(1) Martha paid 10 percent more for the armchair than for the coffee table.
(2) Martha sold the armchair for 20 percent more than she sold the coffee table.
Ans: (E)
這題前輩有討論，以下是前輩的說法
gross profit=sales-cost
(1) Martha paid 10 percent more for the armchair than for the coffee table.
設coffee table' cost=c
則armchair's cost=1.1c
(2) Martha sold the armchair for 20 percent more than she sold the coffee table.
設coffee table' price=s
則armchair's price=1.2s
題目問
(1.2s-1.1c-s-c)/1.2s-1.1c
兩個未知數，故insufficient
(1.2s-1.1c-s-c)/1.2s-1.1c ，我不了解這裡的意思??
為可不能用1.2s-1.1c-s-c)/s-c 呢?
而我當初選的是 C ，是用數字代入滴，是否不能用數字代入算題目呀?
懇請大大的回答
