求一数学题

墨香莉华UID：3030088

A school bus has 10 double seats in each of 2 rows. Two students can sit in each double seat. If an empty bus starts out and makes two stops, picking up three times the number of students at the second stop as at the first stop, and if the bus is then filled to seating capacity, how many students got on the bus as the second stop?  A. 5   B. 10   C. 15 D. 20   E.30   
答案是E  偶以为是B

dandelionttUID：2852417

首先座位是10*2*2=40个
第二站上的人是第一站的三倍，说明第二站的人占了全车的3/4
所以40* 3/4=30
本人数学不好，答案仅供娱乐

SilpakornUID：2988290

应该是那个倍数关系没搞清楚，可以看看陈向东的书。
N times as much A as B / A is N times as much as B都是指A=NB~
所以本题three times the number of students at the second stop as at the first stop
是指第二站上来的是第一站上来的三倍。