y varies directly as x when y=5 , x=20 find y when x=5

Question

finding 'y'

Answer 1

The value 5 for x is a quarter of 20, so y must be reduced by the same factor because it varies directly as x. Therefore y changes from 5 to 5/4 (=1 1/4 or 1.25).

Or, y/x=5/20=1/4, so y=x/4 is the relationship between x and y. Plug x=5 into this formula and we get y=5/4.