May, this is an interesting problem. What it is saying is that the longer the candle, the shorter it will burn. That's what being inversely proportional means.
If they were directly proportional, we keep the same things in the numerators and denominators. 8"/12 minutes = 4"/x minutes, cross multiply and get 8x = 48, so x = 6 minutes.
Since we have inverse proportionality, we keep similar things in the same fraction and flip one. 4"/8" = 12 minutes/x minutes. Cross multiply and get 4x = 96, so x = 24 minutes.
Or, simply put, since the 4 inch candle is half the length of the 8 inch candle, then it will take twice as long to burn.
Hope this helps!
