Answer:
4 Hours
Step-by-step explanation:
we will set up two linear equations first by taking the initial height if each candle and subtracting the rate they burn at times our input variable of time (x) equal to height (y)
So, 8-7/10x=y and 6-1/5x=y
then, because both equations equal y you can set them equal to each other so
8-7/10x=6-1/5x
Finally, solve for x
8-7/10x=6-1/5x
subtract 6 from both sides
2-7/10x=-1/5x
add 7/10 x to both sides (1/5x=2/10x)
2=5/10x
simplify
2=1/2x
x=4
