PP-T1-DS56

[slin0717]

56. 4741-!-item-!-187;#058&004206

During a sale, a clothing store sold each shirt at a price of $15 and each sweater at a price of $25. Did the store sell more sweaters than shirts during the sale?

(1) The average (arithmetic mean) of the prices of all of the shirts and sweaters that the store sold during the sale was $21.

(2) The total of the prices of all of the shirts and sweaters that the store sold during the sale was $420.

答案選(A)

請各位高手指教

[smilego]

shirt 設X件, sweater 設Y 件

1) (15x+25Y)/(x+y) = 21
求得 2y = 3x 可知 y 較大 (充分)
2) 15x + 25y = 420 (不知x,y , 不充分)