Well, 40% is equal to 4/10. So we need to find what value of x will make x/35=4/10
To do this, we need to make the denominators equal. If we multiply 4/10 by 3.5/3.5 (which is another way of saying 1), we get 14/35 because 4*3.5 is 14 and 10*3.5 is 35
if x/35=14/35, then x=14!
We can check our work by dividing 14/35 in a calculator, and we get .4, or 40%.
Hope that helped!