求助新东方模考软件的一道DS题

laiting

During a 3-year period, the profit of company X change by what percent from the second year to the third year?

1)the increase in profits of company X from the first year to the second year was the same increase  from the first year to the third

2) for company X the profits for the first year were 13800 and the profits for the third year were 15900

答案是A

我想不懂，为什么第一年到第二年的增长等于第一年到第三年的增长量就可以直接知道第二年到第三年的增长量？

麻烦各位XDJM了~！

micro_mok

1-2的增长=1-3的增长，so，3的增长=0

laiting

哦哦！对哦！~~ 我真是傻，一大早脑筋就转不过来了！

谢谢！Good Luck!~~