Answer:
9 packages of chocolate bars
Explanation:
Let he bought c packages of chocolate bars and t packages of toffee bars,
Since, he bought 1 fewer package of chocolate bars than toffee bars.
⇒ c = t - 1 -----(1)
Also, he handed out out
of the chocolate bars and
of the toffee bars,
If he handed out the same number of each kind of candy bar.

( By cross multiplication )
( Division property of equality )
From equation (1),





Hence, he bought 9 packages of chocolate bars.