Question

A candle loses height as it burns at a constant rate of 3cm every 12 minutes. If the intitial height of the candle is 15cm , what is the percent decrease in height after it burns for 30 minutes.?

Answer 1

The candle burns at a rate of 3 cm every 12 minutes. After 30 minutes, which is 2.5 times the initial rate time, the candle will have burned 7.5 cm. Therefore, the percent decrease in height after burning for 30 minutes is 50%.

Step-by-step explanation:

We have a candle that burns at a constant rate of 3 cm every 12 minutes. The initial height of the candle is 15 cm, and the question is asking for the percent decrease in height after burning for 30 minutes. To find out the decrease in height, we can set up a proportion.

Time ratio: 12 minutes to 30 minutes is 1:2.5.

Burn rate: 3 cm in 12 minutes, so 3 cm * 2.5 (time ratio) = 7.5 cm in 30 minutes.

Now, we calculate the percent decrease:

Determine the final height: 15 cm - 7.5 cm = 7.5 cm.

Calculate the decrease in height: 15 cm (initial height) - 7.5 cm (final height) = 7.5 cm.

Find the percent decrease: (Decrease in height / Initial height) * 100 = (7.5 cm / 15 cm) * 100 = 50%.

The percent decrease in height after the candle burns for 30 minutes is 50%.

Answer 2

30 mins ÷12 mins

=2.5.

2.5×3=7.5 cm

7.5-3=4.5

4.5 ×100

_____

7.5

=60%