UC知道SAT数学.
来源：百度知道 编辑：UC知道 时间：2024/06/15 05:26:26
有这么两道题
都是同一类
In a community of 416 people, each person owns a dog or a cat or both. If there are 316 dog owners and 280 cat owners, how many of the dog owners own no cat?这道题我会做,但是下面这道却不会,,,为什么,,,而且这道题也绝对不是蒙的,总局的下面这道题少给了个数据似的..
不会的这一题是Each student in a group of 30 students studies German, Italian, or both. The total number of students studying German is three more than the total number of students studying Italian. If the number of students that study both subjects is the same as the number of students that study exactly one subject, how many students in the group study only Italian?
我知道这问题对于大家来说太弱智了
但还是希望解答一下
都是同一类
In a community of 416 people, each person owns a dog or a cat or both. If there are 316 dog owners and 280 cat owners, how many of the dog owners own no cat?这道题我会做,但是下面这道却不会,,,为什么,,,而且这道题也绝对不是蒙的,总局的下面这道题少给了个数据似的..
不会的这一题是Each student in a group of 30 students studies German, Italian, or both. The total number of students studying German is three more than the total number of students studying Italian. If the number of students that study both subjects is the same as the number of students that study exactly one subject, how many students in the group study only Italian?
我知道这问题对于大家来说太弱智了
但还是希望解答一下
我是设方程解的···其实这样挺麻烦的，但比较好理解吧。
设只学德语的有x人，两种都学得是y,只学意大利语的有z人。
这样就是x+y+z=30
X+Y=Y+Z+3
Y=X+Z
得出来就是x=9，y=15，z=6