How many pieces of candy did each kid have?

Question

The kids on Cubbon Street counted all of their Halloween candy. They had 18 pieces of candy in all.

Abby had fewer than 4 pieces of candy.
Billy had twice as much as Abby.
Charlie had twice as much as Billy.
David had 2 pieces more than Abby.

How many pieces of candy did each kid have?

Answer 1

Abby -2
Billy-4(twice as Abby)
Charlie-8(twice as Billy)
David-4(2 pieces more than Abby)

Answer 2

let abby has a candies, billy has b,charlie has c and david has d
b=2a
c=2b => c=4a
d=a+2

now all equation are depending only on the value of a .
it is given that value of a <4
now apply hit and trial for a=1,2 and 3 .
we get
Abby had 2 pieces,
Billy had 4 pieces,
Charlie had 8 pieces,
and David had 4 pieces.