一道GMAT数学题Acertainjuniorclasshas1,000studentsandacertainseniorclasshas800students.Amongthesestudents,thereare60siblingpairs,eachconsistingof1juniorand1senior.Ifstudentistobeselectedatrandomfromeachcla

Question

一道GMAT数学题
A certain junior class has 1,000 students and a certain senior class has 800 students .Among these students ,there are 60 sibling pairs ,each consisting of 1 junior and 1 senior .If student is to be selected at random from each class ,what is the probability that the 2 students selected will be a sibling pair
(A)3/40,000
(B)1/3,600
(C)9/2,000
(D)1/60
(E)1/15

Answer 1

从这些学生中选两人每班选一人的可能情况数：1000*800
从sibling pair中选一对的可能数：60
概率就是3/40000