Answer:
b =

Explanation:
given b is directly proportional to a , then the equation relating them is
b = ka ← k is the constant of proportionality
to find k , substitute b = 3, a = 28 into the equation
3 = 28k ( divide both sides by 28 )
= k
b =
a ← equation of proportionality
to find b when a = 24 , substitute a = 24 into the equation
b =
× 24 ( cancel 28 and 24 by 4 )
b =
× 6 =
=
