### Instruction: A certain junior class has 3000 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?
Answer Choices: (A) 1/40000 (B) 1/3600 (C) 9/2000 (D) 1/60 (E) 1/15.### Response: Let's think about the multi-choice question step by step.
Let's see
Pick 60/3000 first
Then we can only pick 1 other pair from the 800
So total will be 60 / 800 *3000
Simplify and you get 1/40000
The answer is A