Alright first ranks doesn’t mean they’ll get it right. It just means how active the user is. Now to answer your problem, c is given to be 0.5. So 5(0.5) is the same as 5/2, which is 2.5. So 10-2.5=7.5
I think K=1.123 you have to find by how much it's increasing, think of 6(1/2) times WHAT equals 7(1/3) 6(1/2)a=7(1/3) a=1.123 That means each side will be the same times 1.123 x=4.492 you can round that to 4.49 or 4.5 or 5
