If (a) varies directly as (b) and b= 20 when a= 4, find (b) when a=60
I don't understand this question at all
a varied directly as b
means that there is some constant k such that a = kb
That means that a/b = k and is constant. Thus, you want b such that
4/20 = 50/b
4b = 1000
b = 250
Or, since 50 is 12.5 * 4, b = 12.5*20 = 250