Answer :
Elio is right in assuming the relationship between the height and the hours it burns is proportional.
Find the unit rate
14 ÷ 8 = 1.75 cm/h
Divide
21 ÷ 1.75 = 12
You can set this up as an algebraic equation to check the answer.
If the candle is 21 cm tall, it will burn for 12 hours.
Find the unit rate
14 ÷ 8 = 1.75 cm/h
Divide
21 ÷ 1.75 = 12
You can set this up as an algebraic equation to check the answer.
If the candle is 21 cm tall, it will burn for 12 hours.