The mathmatics assignment comprising of 10 questions has been distributed to the class. 4 students, decide to work on assignment together.
Every student goes home and randomly finishes 8 of the 10 questions, and then they meet back together and copy each others work, find probability that all 10 questions will have been replied? (for example, every student could randomly select first eight problems, in which case only first eight have been solved. Or we can say, if 3 students selected for first eight, and one selected last eight, then all 10 questions have been completed.