Answer:
there were 9 plain candles and 3 scented candles.
Explanation:
Let she buys x candles for 4 each and buys y candles for 7 each.
Then According to the questions
x+y= 12.......1
and
4x+7y= 57.........2
solving 1 and 2 we get the values of x and y as 9 and 3 respectively.
So, there were 9 plain candles and 3 scented candles.
