A twelve inch candle and an 18 inch candle are lit at 6pm. The 12 inch candle burns 0.5 inches every hour. The 18 inch candle burns two inches every hour. At what time will the two candles be the same height? Work too please

The simple way is to list the heights each hour next to each other until they match.
If you want to use algebra then
12 - 0.5n = 18 - 2n
2n - 0.5n = 18 - 12
1.5n = 6
n = 6 / 1.5 equals 4
The candles will both be 10 inches tall after 4 hours which is 10pm