Question

A 20-ounce candle is expected to burn for 60 hours. A 12-ounce candle is expected to burn for 36 hours. Assuming the variables are directly related, how many hours would a 9-ounce candle be expected to burn?

18
27
33
45

Answer 1

B. 27.

Explanation:

We have been given that a 20-ounce candle is expected to burn for 60 hours. A 12-ounce candle is expected to burn for 36 hours.

We know that a direct proportional equation is in form
`y=kx`, where k represents constant of proportionality.

Let is find value of k by substituting
`x=20` and
`y=60` in above equation as:

`60=k*20`

`(60)/(20)=(k*20)/(20)`

`3=k`

The equation
`y=3x` represents our given direct proportional relation.

Now, we will substitute
`x=9` to solve for y as:

`y=3*9`

`y=27`

Therefore, a 9-ounce candle would be expected to burn for 27 hours and option B is the correct choice.

Answer 2

divide size of candle by number of hours
to find the rate it burns:

20 ounce / 60 hours = 1/3 ounce per hour

divide 9 ounces by 1/3 ounce per hour to find total time:

9 / 1/3 = 27 hours