Answer:
16.5 cm
Step-by-step explanation:
Rate of burning, R = (height1 - height2) / time of burning
So, R = (19.8cm - 15.9cm) / (27hr - 14hr)
R = 3.9cm / 13hr = 0.3 cm/hr
Now for finding initial height (x) of candle using the same formula but this time we have found the rate of burning
So, 0.3 cm/hr = (x - 19.8cm/hr) / 14hr
0.3 cm/hr x 14hr = x - 19.8cm/hr
so we get x = 24 cm
Now as we got the initial height of the candle now we can get the height (y) after burning for 25 hours.
0.3 cm/hr = (24cm - y) / 25hr
0.3 cm/hr x 25hr = 24cm -y
y = 24cm - 7.5cm = 16.5 cm
So the height of candle after burning for 25 hours is 16.5 cm.
