Posted by Elizabeth on .
Jillian wants to buy candles for winter, in case her electricity and furnace fail. Each candle she plans to use, burns at a rate of 5 mL of was per 15 cm. How many HOURS will it take the candle to burn down completely?
Express the answer to the NEAREST WHOLE NUMBER. (Note: 1mL = 1 cm cubed)
(Hint: A candle is a cylinder; use 3.14 as an estimate for pi.)
I have no idea how to start this. Please show me. Thanks!

Algebra 1 
drwls,
You need to restate the question and look for additional information. 5 ml of WAX per 15 cm is NOT a rate. You need ml per unit time and you also need to know the radius of the candle.
I supect you left out some words by mistake, like the length of time it takes to burn 5 ml, and the radius (which might be what the 15 cm is supposed to be). 
Algebra 1 
Elizabeth,
I'm so sorry, i messed up my spelling.
Each candle she plans to use, burns at a rate of 5 mL of wax per 15 min. One of these candles has a diameter of
8 cm and a height of 15 cm. How many hours will is take the candle to burn down completely? Express your answer to the NEAREST WHOLE NUMBER. (Note: 1mL = 1 cm cubed) (Hint: A candle is a cylinder; use 3.14 as an estimate for pi.) 
Algebra 1 
drwls,
The candle burns at a rate of 5/15 = 1/3 cm^3 (cubic cm) per minute. A candle with the dimensions you described has a volume of
V = (pi*D^2/4)*Height = 753.6 cm^3
The time that it takes to burn is
(Volume)/(burn rate)
= 753.6 cm^3/(1/3 cm^/min)
= 2261 minutes = 37.6 hours. They want you to round that off to 38 hours. 
Algebra 1 
Elizabeth,
how did you get the 2261 min?

Algebra 1 
Elizabeth,
when I divide the volume by the burn rate, i get the answer 251.2 min.