Question

天华书屋进了一批新书,第一天卖出总数的三分之一第二天卖出总数的40%,第二天比第一天多卖出200本

Answer 1

[200 / (40% - 1/3)] * (1 - 1/3 - 40%)

= [200 / (6/15 - 5/15)] * (1 - 5/15 - 6/15)

= [200 / (1/15)] * (4/15)

= 200 * 15 * 4/15

= 800