Carmen burns a candle for 1 hour every night.  A candle will last her 8 nights.  If she burns the candle for 2 hours a night, how many candles will she use over 24 nights?
Burning a candle for 1 hour lasts her 8 nights so if she burns for 2 hours it will last her 8/2 = <<1*8/2=4>>4 nights
1 candle now lasts 4 nights and she needs enough for 24 nights so she needs 24/4 = <<24/4=6>>6 candles
#### 6