Question

某种服装,每件利润为30元,平均每天可销售20件.若每降价1元,则每天可多销售6件.

Answer 1

设定应该降价x元

(30-x) * (20+6x) = 1600

600 + 180x - 20x - 6x2 = 1600

600 + 160x - 6x2 = 1600

160x - 6x2 = 1000

6x2 - 160x + 1000 = 0

3x2 - 80x + 500 = 0

x = 10