A certain junior class has 1000 students and a certain senior class has 800 students. Among these students, there are 60 siblings pairs each consisting of 1 junior and 1 senior. If 1 student is to be selected at random from each class, what is the probability that the 2 students selected will be a sibling pair? Choose the correct choice:
A) 3/40000  B) 1/3600  C) 9/2000  D) 1/60  E) 1/15
There are 60 siblings in junior class and 60 their pair siblings in the senior class. We want to determine probability of choosing one sibling from junior class and its pair from senior.   What is the probability of choosing ANY sibling from junior class? 60/1000 (as there are 60 of them).   What is the probability of choosing PAIR OF CHOSEN SIBLING in senior class? As in senior class there is only one pair of chosen sibling it would be 1/800 (as there is only one sibling pair of chosen one).   So the probability of that the 2 students selected will be a sibling pair is: 60/1000∗1/800=3/40000   3/40000nswer: 3/40000.
<result>A</result>
A certain junior class has 1000 students and a certain senior class has 800 students. Among these students, there are 60 siblings pairs each consisting of 1 junior and 1 senior. If 1 student is to be selected at random from each class, what is the probability that the 2 students selected will be a sibling pair?