Answer:
![4-0.6x=1.5](https://img.qammunity.org/2020/formulas/mathematics/middle-school/mcgqxldi2enw7bigk9qx8h3kuxn4zo0fpd.png)
4.2 hours.
Explanation:
Let x represent number of hours.
We have been given that a candle burns at the rate of 0.6 inches per hour. So amount of candle burned in x hours would be
.
We have been given that the candle was 4 inches tall, so height of candle left after x hours would be
.
The height of the candle after x hours is 1.5 inches. We can represent this information in an equation as:
![4-0.6x=1.5](https://img.qammunity.org/2020/formulas/mathematics/middle-school/mcgqxldi2enw7bigk9qx8h3kuxn4zo0fpd.png)
![4-4-0.6x=1.5-4](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ngry0pdlvtjy9avm8fyue7j0oq5732fyai.png)
![-0.6x=-2.5](https://img.qammunity.org/2020/formulas/mathematics/middle-school/t2ay3nqd9uja7vgnuzn02psvvsuunyqzuc.png)
![(-0.6x)/(-0.6)=(-2.5)/(-0.6)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/hjwasvlkqgal0ie3s1o3qxoeabqw2bt64y.png)
![x=4.166](https://img.qammunity.org/2020/formulas/mathematics/middle-school/6fb2c5hiysk3gocc3ehyv23eepjiwpf57o.png)
Therefore, the candle will be melted to 1.5 inches in approximately 4.2 hours.