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 11 hours of burning, a candle has a height of 27.9 centimeters. After 30 hours of burning, its height is 26 centimeters. What is the height of the candle after 20 hours?

Answer 1

Answer:

y = 27 cm

Explanation:

given,

After 11 hours of burning height of candle is 27.9 cm

After 30 hours of burning height of candle is 26 cm

height after 20 hour = ?

the candle height decreases linearly

using linear equation

y = m x+ c

27.9 = m (11 ) + C.......(1)

26 = m (30) + C..............(2)

on solving equation (1) and (2)

1.9 = -19 m

m = -0.1

from equation 2

26 = -3 + C

C = 29

y = m x + 29

at 20 hour

y = -0.1× 20 + 29

y = 27

height of candle after 20 hours is 27 cm.