Problema Solution
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`4 hours of burning, a candle has a height of 22 centimeters. After 25 hours of burning, its height is 16.5 centimeters. What is the height of the candle after 21 hours?
Answer provided by our tutors
The height of the candle is 20.5 centermeters after burning 15hours
After burning 9 hours, the height is 21.1centerneters
After burning 28 hours, the height is 19.2 centermeters.
The height burned up during the 19 (28 - 9)hours is 1.9 centermeter (21.1-19.2). the buring speed per hour is 1.9/19=0.1 cm/hour
After burning 15 hours, the height burned up is (15 - 9) x 0.1 = 0.6 cm,
The left height is 21.1 - 0.6 = 20.5 cm