it is rather easy, in the first task you need to multiply 4x3x2x1 then you will have all the possibilities, to next task i would suggest you to do it across , i mean 1/15 -- 30 and below 1/10 -- x , multiply across, and you have a right answer
good luck
hello ,
i would like to find out somoething more abaut this experiment, i got the general drift , but what is it for? What advantages can we gain in our life from this? I trully believe that someone can help me, looking froward to answer
thanks