og13 71 题。。。求大家帮忙解答

萧章may

不明白答案为什么n＋1.2n＝2420？ 求详解谢谢大家关照

71.Yesterday's closing prices of 2,420 different stocks
listed on a certain stock exchange were all different
from today's closing prices. The number of stocks
that closed at a higher price today than yesterday was
20 percent greater than the numberthat closed at a
lower price. How many of the stocks closed at a
higher price today than yesterday?
(A)484
(B)726
(01,100
(D)1,320
(E)1,694