word problem

Question

Suppose that the height (in centimeters) of a candle is a linear function of the amount of time (in hours) it has been burning. After 13 hours of burning, a candle has a height of 13.2 centimeters. After 27 hours of burning, its height is 4.8 centimeters. What is the height of the candle after 19 hours?

Answer 1

after 13 hours the candle has a height of 13.2 cm

after 27 hours the candle has a height of 4.8 cm

after 27-13=14 hours, the candle has gone down 13.2-4.8=8.4 cm

the candle has gone down 8.4 cm in 14 hours

how much does the candle burn every hour ?

8.4/14=0.6 cm of the candle is burned every hour

after 13 hours the candle is at 13.2 cm

after 19 hours the candle is at what height ?

19-13=6 hours of burning at the rate of 0.6 cm per hour

in 6 hours the candle burns 6*0.6=3.6 cm

the candle was at 13.2 cm after 13 hours

in the next 6 hours it burned down 3.6 cm

13.2-3.6=9.6 cm is the height of the candle after 19 hours