</span><span>if you have 21 bins then the 'middle bin' is bin 11 (starting at 1) </span> <span>So the 'mean' of this distribution is 11. </span> <span>Therefore from 1000 balls the number of balls is 0.91 x 1000. </span> So therefore the answer would be C
3m-3. basically since 6 and -9 don’t have any variables, you would ignore the 3m to combine them like 6-9, which would be -3 and then adding that onto the 3m you would get 3m-3