我又来了求数学题好几道 （我明天考试啊...)

cyvivi

(1)  all the trainees in a certain aviator training program must take both a written test and a fight test. if 70 percent of the trainees passed the written test and 80 percent of the trainees passed the flight test what percent of the trainees passed both tests?
1) 10 percent of the trainees did not pass either test
2) 20 percent of the trainees passed onlhy the flight test.


谢谢各位

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(2)
how many integers between 1 and 100, inclusive, can be divided by none of 2,3,and 5
1)24
2)26
3)28
4)30
5)32


（3）in a marketing servey for products some people were asked which of the products, if any, they use. of the people surveyed, a total of 400 use A, a total of 400 use B, a total of 450 use C, a total 200 use A and B simultaneously, a total of 175 use B and C simultaneously, a total of 200 use C and AA simultaneously, a total of 75 useA, B，C simultaneously, and a total of 200 use non of the products. How many people were surveyed?
1)950
2)950
3)1000
4)1025
5)1050

谢谢各位cd大侠了，我现在先去做别的，明天过来check
sets是我的死穴啊，拜托尽量的讲详细一些

cyvivi

把自己顶起来~~

windparis

对的，应该是each都可以的

cyvivi

是不是 70%+80%-x+10%=100%