prep-t1 DS 135

[w062611]

During a one-day sale, a store sold each sweater of a certain type for $30 more than the store's cost to purchase each sweater. How many of these sweaters were sold during the sale?

(1) During the sale, the total revenue from the sale of these sweaters was $270.

(2) During the sale, the store sold each of these sweaters at a price that was 50 percent greater than the store's cost to purchase each sweater.


答案為 C

我怎麼看都覺得A就行了

請高手指導一下此題如何解

選項2也看不太懂其意思

感謝指教

[dibert8]

(1) (C + 30) * N = 270
(2) C + 30 = (1 + 50%) * C
(2) 只能求出 C, 必需 (1) & (2) 才能求出 N.