求教ps

pipa66

求教ps。多谢！
16. In each production lot for a certain toy, 25 percent of the toys are red and 75 percent of the toys are blue. Half the toys are size A and half are size B. If 10 out of a lot of 100 toys are red and size A, how many of the toys are blue and size B?
(A) 15 (B) 25 (C) 30
(D) 35 (E) 40
答案为D

全无头绪，怎解？

equilibrium

100个球中25个红球,75个兰球
50个A, 50个B,
25个红球中有10个是A,所以还有15个红球是B
那么剩下的兰色B球就是50-15=35个