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!
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).
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.)
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.
how did you get the 2261 min?
when I divide the volume by the burn rate, i get the answer 251.2 min.
To determine the number of hours it takes for the candle to burn down completely, we need to calculate the volume of wax consumed per hour.
First, let's determine the volume of wax consumed per centimeter burnt. Since each candle burns at a rate of 5 mL of wax per 15 cm, we can calculate the volume of wax consumed per centimeter:
Volume of wax consumed per cm = (5 mL) / (15 cm) = 1/3 mL/cm
Next, let's calculate the volume of the candle. Since we know that 1 mL is equivalent to 1 cm³, we can consider the volume of wax consumed per centimeter as the same volume of the candle burnt.
The volume of a cylinder (such as a candle) is calculated using the formula:
Volume = π * r² * h
In this case, we don't know the radius or height of the candle, so we need to find one of them. Since we have the information about the volume of wax consumed per centimeter, we can assume that this volume is the same as the volume of the cylinder burned per centimeter.
So, we have:
Volume of candle burned per cm = 1/3 cm³
Assuming the radius of the candle is r and the height is h, we can calculate the volume of the candle:
Volume of candle = π * r² * h
Setting the volume of the candle equal to the volume consumed per centimeter, we get:
π * r² * h = 1/3 cm³
To calculate the time it takes for the candle to burn down completely, we need to know the total height of the candle. Without this information, it is not possible to provide a specific answer regarding the number of hours.