SP003 Maths Paper 1 Booklet A – Question 14

A, B and C are three bottles with the same capacity.
At first, bottle A was completely filled with water,
and bottles B and C were each $\dfrac{1}{7}$ filled.
Jeremy poured out some water from A to B and C.
Then all the containers had the same amount of water.
What fraction of the water did Jeremy pour out from A?
(1) $\dfrac{2}{7}$
(2) $\dfrac{4}{7}$
(3) $\dfrac{2}{9}$
(4) $\dfrac{4}{9}$